deamino-arginine-vasopressin and Disease-Models--Animal

Since its discovery, arginine vasopressin (AVP) was subjected to several modifications with the aim of obtaining novel derivatives with increased potency and selectivity for biomedical use. Desmopressin (dDAVP) is a first generation synthetic analog of AVP with hemostatic and antimetastatic activity. dDAVP acts as a selective agonist of the arginine vasopressin type 2 receptor (AVPR2) present in microvascular endothelium and cancer cells. Considering its selective effects on AVPR2-expressing malignant and vascular tissue, and interesting antitumor profile, dDAVP was used as a lead compound for the development of novel peptide analogs with enhanced anticancer efficacy. After conducting different structure-activity relationship studies to determine key aminoacidic positions for its antitumor activity against AVPR2-expressing malignant cells, dDAVP was rationally modified and a wide panel of synthetic analogs with different sequence and structural modifications was assessed. As a result of this structure-based drug derivatization novel AVP analog [V

Topics: Animals; Antineoplastic Agents; Deamino Arginine Vasopressin; Disease Models, Animal; Mice; Neoplasms; Receptors, Vasopressin

Disruption of water and electrolyte balance is frequently encountered in clinical medicine. Regulating water metabolism is critically important. Diabetes insipidus (DI) presented with excessive water loss from the kidney is a major disorder of water metabolism. To understand the molecular and cellular mechanisms and pathophysiology of DI and rationales of clinical management of DI is important for both research and clinical practice. This chapter will first review various forms of DI focusing on central diabetes insipidus (CDI) and nephrogenic diabetes insipidus (NDI ) . This is followed by a discussion of regulatory mechanisms underlying CDI and NDI , with a focus on the regulatory axis of vasopressin, vasopressin receptor 2 (V2R ) and the water channel molecule, aquaporin 2 (AQP2 ). The clinical manifestation, diagnosis and management of various forms of DI will also be discussed with highlights of some of the latest therapeutic strategies that are developed from in vitro experiments and animal studies.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antidiuretic Agents; Aquaporin 2; Deamino Arginine Vasopressin; Diabetes Insipidus; Disease Models, Animal; Gene Expression Regulation; Humans; Kidney; Phosphodiesterase Inhibitors; Protein Isoforms; Receptors, Vasopressin; Vasopressins; Water; Water-Electrolyte Balance

The total restoration of urinary concentrating ability of the DI rat given daily injections of vasopressin takes several weeks, although complete osmotic equilibrium across the collecting duct is manifest within hours. This suggests that there may be other deficiencies of the renal concentrating mechanism that, if corrected by vasopressin treatment, are corrected more slowly. I have focussed on just three possibilities. First, the morphology of the medullary interstitium is different from normal rats. Perhaps associated with this finding are alterations in the levels of medullary glycosaminoglycans which may have a role to play in water balance. Functional and morphological changes in the juxtamedullary nephrons are also evident. Second, the possibility exists that the countercurrent multiplier of the DI rat operates less efficiently than in the normal animal. Finally, reduced synthesis of PGs in the renal medulla of DI rats may also influence the concentrating mechanism, although in a favorable direction. While most (if not all) of these differences are secondary to the lack of vasopressin, in some instances it appears that it is the high water turnover (possibly the altered chemical composition of the medullary interstitium) that is the primary culprit. While the DI rat remains an excellent model for the study of water balance and the action of vasopressin, the presence of multiple defects within the system should be borne in mind. This is particularly true when comparing data obtained following acute treatment with vasopressin versus that following chronic treatment.

Topics: Adenylyl Cyclases; Animals; Arginine Vasopressin; Deamino Arginine Vasopressin; Diabetes Insipidus; Disease Models, Animal; Glomerular Filtration Rate; Glycosaminoglycans; Kidney; Kidney Concentrating Ability; Kidney Medulla; Loop of Henle; Nephrons; Osmolar Concentration; Prostaglandins; Rats; Rats, Brattleboro; Rats, Mutant Strains; Vasopressins; Water-Electrolyte Imbalance

Topics: Animals; Antigens; Bleeding Time; Blood Platelets; Blood Transfusion; Cattle; Chemical Phenomena; Chemistry, Physical; Deamino Arginine Vasopressin; Disease Models, Animal; Endothelium; Factor VIII; Fibrinogen; Glycoproteins; Humans; Megakaryocytes; Platelet Adhesiveness; Rabbits; Swine; von Willebrand Diseases; von Willebrand Factor

Apelin and arginine-vasopressin (AVP) are conversely regulated by osmotic stimuli. We therefore hypothesized that activating the apelin receptor (apelin-R) with LIT01-196, a metabolically stable apelin-17 analog, may be beneficial for treating the Syndrome of Inappropriate Antidiuresis, in which AVP hypersecretion leads to hyponatremia. We show that LIT01-196, which behaves as a potent full agonist for the apelin-R, has an in vivo half-life of 156 minutes in the bloodstream after subcutaneous administration in control rats. In collecting ducts, LIT01-196 decreases dDAVP-induced cAMP production and apical cell surface expression of phosphorylated aquaporin 2 via AVP type 2 receptors, leading to an increase in aqueous diuresis. In a rat experimental model of AVP-induced hyponatremia, LIT01-196 subcutaneously administered blocks the antidiuretic effect of AVP and the AVP-induced increase in urinary osmolality and induces a progressive improvement of hyponatremia. Our data suggest that apelin-R activation constitutes an original approach for hyponatremia treatment.

Topics: Amino Acid Sequence; Animals; Apelin; Apelin Receptors; Arginine Vasopressin; Blood Glucose; Blood Pressure; Cell Line; Colforsin; Cyclic AMP; Deamino Arginine Vasopressin; Disease Models, Animal; Diuresis; Electrolytes; Half-Life; Hyponatremia; Kidney Tubules, Collecting; Male; Mice; Models, Biological; Myocardial Contraction; Peptides; Phosphorylation; Rats, Sprague-Dawley; Tolvaptan

The association between diabetes insipidus (DI) and chronic dietary K

Topics: Animals; Antidiuretic Agents; Aquaporin 2; Deamino Arginine Vasopressin; Diabetes Insipidus, Nephrogenic; Disease Models, Animal; Drug Resistance; Female; Kidney; Male; Mice, Inbred C57BL; Phosphorylation; Potassium Deficiency; Potassium, Dietary; Risk Factors; Sex Characteristics; Water-Electrolyte Balance

The most used experimental mouse model of hyponatremia and elevated intracranial pressure (ICP) is intraperitoneal injection of water in combination with antidiuretics. This model of water intoxication (WI) results in extreme pathological changes and death within 1 h. To improve preclinical studies of the pathophysiology of elevated ICP, we characterized diuresis, cardiovascular parameters, blood ionogram and effects of antidiuretics in this model. We subsequently developed a new mouse model with mild hyponatremia and sustained increased ICP. To investigate the classical protocol (severe WI), C57BL/6mice were anesthetized and received an intraperitoneal injection of 20% body weight of MilliQ water with or without 0.4 µg·kg

Topics: Animals; Antidiuretic Agents; Deamino Arginine Vasopressin; Disease Models, Animal; Hyponatremia; Injections, Intraperitoneal; Intracranial Hypertension; Intracranial Pressure; Male; Mice; Mice, Inbred C57BL; Water Intoxication

Demyelinated lesions in human pons observed after osmotic shifts in serum have been referred to as central pontine myelinolysis (CPM). Astrocytic damage, which is prominent in neuroinflammatory diseases like neuromyelitis optica (NMO) and multiple sclerosis (MS), is considered the primary event during formation of CPM lesions. Although more data on the effects of astrocyte-derived factors on oligodendrocyte precursor cells (OPCs) and remyelination are emerging, still little is known about remyelination of lesions with primary astrocytic loss. In autopsy tissue from patients with CPM as well as in an experimental model, we were able to characterize OPC activation and differentiation. Injections of the thymidine-analogue BrdU traced the maturation of OPCs activated in early astrocyte-depleted lesions. We observed rapid activation of the parenchymal NG2

Topics: Adult; Aged; Animals; Antidiuretic Agents; Astrocytes; Cell Differentiation; Cell Lineage; Deamino Arginine Vasopressin; Demyelinating Diseases; Disease Models, Animal; Female; Humans; Lateral Ventricles; Male; Middle Aged; Myelin Sheath; Myelinolysis, Central Pontine; Neoplasm Proteins; Nestin; Neural Stem Cells; Oligodendrocyte Precursor Cells; Oligodendroglia; Rats; Sodium Chloride

Control of metastatic spread of colorectal cancer (CRC) remains as a major therapeutic challenge. [V4 Q5 ]dDAVP is a vasopressin peptide analog with previously reported anticancer activity against carcinoma tumors. By acting as a selective agonist of arginine vasopressin type 2 membrane receptor (AVPR2) present in endothelial and tumor cells, [V4Q5]dDAVP is able to impair tumor aggressiveness and distant spread. Our aim was to evaluate the potential therapeutic benefits of [V4Q5]dDAVP on highly aggressive CRC disease using experimental models with translational relevance.. Murine CT-26 and human Colo-205 AVPR2-expressing CRC cell lines were used to test the preclinical efficacy of [V4Q5]dDAVP, both in vitro and in vivo.. In syngeneic mice surgically implanted with CT-26 cells in the spleen, sustained intravenous treatment with [V4Q5]dDAVP (0.3 µg/kg) dramatically impaired metastatic progression to liver without overt signs of toxicity, and also reduced experimental lung colonization. The compound inhibited in vivo angiogenesis driven by Colo-205 cells in athymic mice, as well as in vitro endothelial cell migration and capillary tube formation. [V4Q5]dDAVP exerted AVPR2-dependent cytostatic activity in vitro (IC50 1.08 µM) and addition to 5-fluorouracil resulted in synergistic antiproliferative effects both in CT-26 and Colo-205 cells.. The present preclinical study establishes for the first time the efficacy of [V4Q5]dDAVP on CRC. These encouraging.. suggest that the novel second generation vasopressin analog could be used for the management of aggressive CRC as an adjuvant agent during surgery or to complement standard chemotherapy, limiting tumor angiogenesis and metastasis and thus protecting the patient from CRC recurrence.

Topics: Angiogenesis Inhibitors; Animals; Cell Line, Tumor; Cell Proliferation; Cell Survival; Colorectal Neoplasms; Deamino Arginine Vasopressin; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Humans; Liver Neoplasms; Lung Neoplasms; Mice; Neoplasm Metastasis; Neoplasm Staging; Neovascularization, Pathologic; Receptors, Vasopressin; Xenograft Model Antitumor Assays

The collecting duct (CD) concentrates the urine, thereby maintaining body water volume and plasma osmolality within a normal range. The endocrine hormone arginine vasopressin acts in the CD to increase water permeability via the vasopressin 2 receptor (V2R)-aquaporin (AQP) axis. Recent studies have suggested that autocrine factors may also contribute to the regulation of CD water permeability. Nitric oxide is produced predominantly by nitric oxide synthase 1 (NOS1) in the CD and acts as a diuretic during salt loading. The present study sought to determine whether CD NOS1 regulates diuresis during changes in hydration status. Male and female control and CD NOS1 knockout (CDNOS1KO) mice were hydrated (5% sucrose water), water deprived, or acutely challenged with the V2R agonist desmopressin. In male mice, water deprivation resulted in decreased urine flow and increased plasma osmolality, copeptin concentration, and kidney AQP2 abundance independent of CD NOS1. In female control mice, water deprivation reduced urine flow, increased plasma osmolality and copeptin, but did not significantly change total AQP2; however, there was increased basolateral AQP3 localization. Surprisingly, female CDNOS1KO mice while on the sucrose water presented with symptoms of dehydration. Fibroblast growth factor 21, an endocrine regulator of sweetness preference, was significantly higher in female CDNOS1KO mice, suggesting that this was reducing their drive to drink the sucrose water. With acute desmopressin challenge, female CDNOS1KO mice failed to appropriately concentrate their urine, resulting in higher plasma osmolality than controls. In conclusion, CD NOS1 plays only a minor role in urine-concentrating mechanisms.

Topics: Animals; Antidiuretic Agents; Aquaporin 2; Aquaporin 3; Deamino Arginine Vasopressin; Dehydration; Disease Models, Animal; Diuresis; Female; Fibroblast Growth Factors; Kidney Concentrating Ability; Kidney Tubules, Collecting; Male; Mice, Knockout; Nitric Oxide; Nitric Oxide Synthase Type I; Organism Hydration Status; Osmolar Concentration; Sex Factors; Signal Transduction; Urodynamics; Water Deprivation

In the syndrome of inappropriate antidiuretic hormone secretion (SIADH), hyponatremia is limited by onset of vasopressin-escape caused by loss of the water channel aquaporin-2 in the renal collecting duct despite high circulating vasopressin. Here, we use the methods of systems biology in a well-established rat model of SIADH to identify signaling pathways activated at the onset of vasopressin-escape. Using single-tubule RNA-Seq, full transcriptomes were determined in microdissected cortical collecting ducts of vasopressin-treated rats at 1, 2, and 4 days after initiation of oral water loading in comparison to time-control rats without water loading. The time-dependent mRNA abundance changes were mapped to gene sets associated with curated canonical signaling pathways and revealed evidence of perturbation of transforming growth factor β signaling and epithelial-to-mesenchymal transition on Day 1 of water loading simultaneous with the initial fall in Aqp2 gene expression. On Day 2 of water loading, transcriptomic changes mapped to Notch signaling and the transition from G0 into the cell cycle but arrest at the G2/M stage. There was no evidence of cell proliferation or altered principal or intercalated cell numbers. Exposure of vasopressin-treated cultured mpkCCD cells to transforming growth factor β resulted in a virtually complete loss of aquaporin-2. Thus, there is a partial epithelial-to-mesenchymal transition during vasopressin escape with a subsequent shift from quiescence into the cell cycle with eventual arrest and loss of aquaporin-2.

Topics: Animals; Aquaporin 2; Cell Proliferation; Cells, Cultured; Cellular Senescence; Deamino Arginine Vasopressin; Disease Models, Animal; Drinking; Epithelial-Mesenchymal Transition; Gene Expression Profiling; Gene Expression Regulation; Hyponatremia; Inappropriate ADH Syndrome; Kidney Tubules, Collecting; Male; Rats, Sprague-Dawley; Receptors, Notch; RNA, Messenger; Sequence Analysis, RNA; Signal Transduction; Systems Biology; Time Factors; Transcription, Genetic; Transcriptome; Transforming Growth Factor beta

Glioblastoma is a devastating malignancy with a dismal survival rate. Currently, there are limited prognostic markers of glioblastoma including IDH1, ATRX, MGMT, PTEN, EGFRvIII, and others. Although these biomarkers for tumor prognosis are available, a surgical biopsy must be performed for these analyses, which has morbidity involved. A non-invasive and readily available biomarker is sought after which provides clinicians prognostic information. Sodium is an electrolyte that is easily and quickly obtained through analysis of a patient's serum. Hyponatremia has been shown to have a predictive and negative prognostic indication in multiple cancer types, but the role of glioblastoma patients' serum sodium at the time of diagnosis in predicting glioblastoma patient survival has not been determined. We assessed whether hyponatremia at the time of glioblastoma diagnosis correlates to patient survival and show that in our cohort of 200 glioblastoma patients, sodium, at any level, did not significantly correlate to glioblastoma survival, unlike what is seen in multiple other cancer types. We further demonstrate that inducing hyponatremia in an orthotopic murine model of glioblastoma has no effects on tumor progression and survival.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Antidiuretic Agents; Brain Neoplasms; Child; Child, Preschool; Deamino Arginine Vasopressin; Disease Models, Animal; Female; Glioblastoma; Humans; Hyponatremia; Male; Middle Aged; Sodium; Young Adult

A vasopressin-induced endoymphatic hydrops model can represent an acute vertiginous attack in Menière's disease (MD).. Previous animal models are not appropriate to evaluate the efficacy of new treatments for hydrops because they cannot represent an acute attack of MD. Recently, a new dynamic model was introduced for acute hydrops exacerbation using the vasopressin type 2 receptor agonist, desmopressin (1-deamino-8-D-Arginine vasopressin, VP); however, resulting changes in vestibular function have not been investigated.. A total of 37 guinea pigs were used. Two to 4 weeks after surgical ablation of endolymphatic sacs in 33 guinea pigs, acute exacerbation of hydrops was induced by a single VP injection in 18 animals (group A). Next, two VP injections at 1 hour interval were administered to investigate the effect of multiple VP doses on vestibular function in the other 15 animals (group B). In the remaining four animals, VP was injected without surgery for the control group (control). Bidirectional sinusoidal harmonic acceleration (SHA) tests of vestibular function were performed. "Type I response" was defined as when the maximum slow-phase velocity (SPV) during left rotation (toward the operated ear) was lower than that during right rotation (toward the normal ear). In contrast, "Type II response" was defined as when maximum SPV at the left rotation was higher than that at the right rotation. Vestibular symmetry scores were analyzed at baseline and after each of two VP injections given 1 hour apart.. Vestibular symmetry scores increased at 1 hour after VP injection in all 18 animals in group A (p < 0.001). Two hours after VP injection, symmetry score decreased to the initial score. Two different types of vestibular response were observed after VP. However, the symmetry scores between type I and II responses were not significantly different (p = 0.173). In all 15 animals of Group B, vestibular asymmetry was sustained over 3 hours when two VP injections were given 1 hour apart. In three of Group B, the type of vestibular response changed from type II response to type I response after the 2nd VP injection; however, no animal demonstrated a shift from type I to type II response.. VP can transiently induce an acute exacerbation of hydrops and asymmetric vestibular dysfunction in guinea pigs. This model could help in studying new treatments for acute hydrops and in explaining the mechanism of bidirectional nystagmus in MD.

Topics: Acceleration; Animals; Deamino Arginine Vasopressin; Disease Models, Animal; Endolymphatic Hydrops; Endolymphatic Sac; Functional Laterality; Guinea Pigs; Recovery of Function; Rotation; Vertigo; Vestibular Function Tests

Blood flow to the intestine is decreased in sepsis in favor of vital organs resulting in ischemic damage of the gut mucosa. Once the mucosa is damaged, increased translocation of intestinal bacteria to the systemic circulation may occur. This in turn aggravates the inflammatory response contributing to the development of multi-organ failure. Desmopressin is a synthetic analog of vasopressin, an anti-diuretic hormone which has been shown to induce vasodilation and is thought to be implicated in immunomodulation. In this study, we investigate the effects of desmopressin on the intestinal microcirculation during sepsis in an experimental endotoxemia model in rats using intravital microscopy. In addition, we investigate the effects of desmopressin on systemic inflammation.. Forty Lewis rats were subdivided into four groups, where rats received intravenous saline (control), desmopressin (1μg/kg/ml), lipopolysaccharide (5mg/kg) or lipopolysaccharide followed by desmopressin. Inflammatory response was assessed by quantifying the number of temporary and firmly adherent leukocytes in submucosal venules. Capillary perfusion was determined by assessing the number of functional, non-functional and dysfunctional capillaries in the intestinal wall layers (muscularis longitudinalis, muscularis circularis and mucosa). Additionally, inflammatory cytokine levels were determined by multiplex assays.. The number of firmly adhering leukocytes in V1 venules of rats receiving lipopolysaccharide and treated with desmopressin was significantly reduced compared to lipopolysaccharide only group (LPS: 259±25.7 vs. LPS+DDAVP: 203±17.2; n/mm(2); p<0.05). Additionally, desmopressin treatment improved impaired intestinal microcirculation by improving functional capillary density following lipopolysaccharide administration in all examined layers of the intestinal wall. We also observed a significant decrease in TNF-α levels in rats which received desmopressin in endotoxemia compared to untreated rats (LPS: 383±64.2; LPS+DDAVP: 261.3±22; pg/ml; p<0.05).. Desmopressin administration improved intestinal capillary perfusion and reduced inflammatory response in rat endotoxemia.

Topics: Animals; Anti-Inflammatory Agents; Arterial Pressure; Blood Flow Velocity; Capillaries; Deamino Arginine Vasopressin; Disease Models, Animal; Endotoxemia; Heart Rate; Inflammation Mediators; Intestines; Leukocyte Rolling; Leukocytes; Lipopolysaccharides; Male; Microcirculation; Microscopy, Fluorescence; Microscopy, Video; Rats, Inbred Lew; Splanchnic Circulation; Time Factors

Autosomal dominant polycystic kidney disease (ADPKD) is a leading cause of ESRD. A central defect associated with ADPKD pathology is elevated levels of 3', 5'-cyclic AMP (cAMP). Compounds such as tolvaptan and pasireotide, which indirectly reduce adenylyl cyclase 6 (AC6) activity, have hence proven effective in slowing cyst progression. Here, we tested the efficacy of these compounds individually and in combination in a hypomorphic PKD1 model, Pkd1(R3277C/R3277C) (Pkd1(RC/RC)), in a 5-month preclinical trial. Initially, the Pkd1(RC/RC) model was inbred into the C57BL/6 background, minimizing disease variability, and the pathogenic effect of elevating cAMP was confirmed by treatment with the AC6 stimulant desmopressin. Treatment with tolvaptan or pasireotide alone markedly reduced cyst progression and in combination showed a clear additive effect. Furthermore, combination treatment significantly reduced cystic and fibrotic volume and decreased cAMP to wild-type levels. We also showed that Pkd1(RC/RC) mice experience hepatic hypertrophy that can be corrected by pasireotide. The observed additive effect reinforces the central role of AC6 and cAMP in ADPKD pathogenesis and highlights the likely benefit of combination therapy for patients with ADPKD.

Topics: Animals; Antidiuretic Agents; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Cell Line, Tumor; Cell Membrane; Cyclic AMP; Deamino Arginine Vasopressin; Disease Models, Animal; Drug Therapy, Combination; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microsatellite Repeats; Models, Genetic; Polycystic Kidney, Autosomal Dominant; Somatostatin; Tolvaptan; TRPP Cation Channels

Overly rapid correction of chronic hyponatremia can cause osmotic demyelination syndrome (ODS). Minocycline protects ODS associated with overly rapid correction of chronic hyponatremia with hypertonic saline infusion in rats. In clinical practice, inadvertent rapid correction frequently occurs due to water diuresis, when vasopressin action suddenly ceases. In addition, vasopressin receptor antagonists have been applied to treat hyponatremia. Here the susceptibility to and pathology of ODS were evaluated using rat models developed to represent rapid correction of chronic hyponatremia in the clinical setting. The protective effect of minocycline against ODS was assessed. Chronic hyponatremia was rapidly corrected by 1 (T1) or 10 mg/kg (T10) of tolvaptan, removal of desmopressin infusion pumps (RP), or administration of hypertonic saline. The severity of neurological impairment in the T1 group was significantly milder than in other groups and brain hemorrhage was found only in the T10 and desmopressin infusion removal groups. Minocycline inhibited demyelination in the T1 group. Further, immunohistochemistry showed loss of aquaporin-4 (AQP4) in astrocytes before demyelination developed. Interestingly, serum AQP4 levels were associated with neurological impairments. Thus, minocycline can prevent ODS caused by overly rapid correction of hyponatremia due to water diuresis associated with vasopressin action suppression. Increased serum AQP4 levels may be a predictive marker for ODS.

Topics: Animals; Antidiuretic Hormone Receptor Antagonists; Aquaporin 4; Astrocytes; Behavior, Animal; Benzazepines; Biomarkers; Brain; Chemokines; Cytokines; Cytoprotection; Deamino Arginine Vasopressin; Demyelinating Diseases; Disease Models, Animal; Diuresis; Hyponatremia; Intracranial Hemorrhages; Male; Matrix Metalloproteinases; Minocycline; Neuroprotective Agents; Osmosis; Rats, Sprague-Dawley; Saline Solution, Hypertonic; Sodium; Therapeutics; Time Factors; Tolvaptan; Water-Electrolyte Balance

One of the clinical alterations observed in chronic renal disease (CRD) is the impaired urine concentration, known as diabetes insipidus (DI). Tubulointerstitial fibrosis of the kidney is also a pathological finding observed in CRD and involves composition of extracellular matrix (ECM). However, an association between these two events has not been elucidated. In this study, we showed that the extracellular-to-intracellular scaffold protein integrin-linked kinase (ILK) regulates expression of tubular water channel aquaporin-2 (AQP2) and its apical membrane presence in the renal tubule. Basally, polyuria and decreased urine osmolality were present in ILK conditional-knockdown (cKD-ILK) adult mice compared with nondepleted ILK littermates. No changes were observed in arginine-vasopressin (AVP) blood levels, renal receptor (V2R), or AQP3 expression. However, tubular AQP2 was decreased in expression and apical membrane presence in cKD-ILK mice, where the canonical V2R/cAMP axis activation is still functional, but independent of the absence of ILK. Thus, cKD-ILK constitutes a nephrogenic diabetes insipidus (NDI) model. AQP2 and ILK colocalize in cultured inner medullary collecting duct (mIMCD3) cells. Specific ILK siRNAs and collagen I (Col) decrease ILK and AQP2 levels and AQP2 presence on the membrane of tubular mIMCD3 cells, which impairs the capacity of the cells to transport water under hypotonic stress. The present work points to ILK as a therapeutic target in NDI.

Topics: Animals; Aquaporin 2; Aquaporin 3; Arginine Vasopressin; Biological Transport, Active; Body Water; Cell Membrane; Cell Polarity; Cells, Cultured; Collagen Type I; Deamino Arginine Vasopressin; Diabetes Insipidus, Nephrogenic; Disease Models, Animal; Extracellular Matrix Proteins; Kidney Concentrating Ability; Kidney Tubules, Collecting; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Osmolar Concentration; Osmotic Pressure; Phosphorylation; Polyuria; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Receptors, Vasopressin; RNA Interference; RNA, Small Interfering

Desmopressin (dDAVP) is a synthetic peptide analog of vasopressin with antidiuretic and hemostatic properties. Recent experimental evidence have suggested that dDAVP can inhibit metastasis formation by agonist action on V2 vasopressin receptors present in both tumor and endothelial cells. We have examined the kinetics of dDAVP effect during metastatic colonization and its potential association with hemostasis.. The experimental metastasis assay was performed by injecting F3II mammary carcinoma cells into the lateral tail vein of syngeneic female BALB/c mice.. Clinically relevant doses of dDAVP (0.3 to 2 μg/kg intravenously (i.v.)) produced a dose-dependent inhibition in the formation of lung nodules when administered during the first 24 hours after F3II tumor cell injection. The hemostatic agent tranexamic acid (10 mg/kg, i.v.) had no effect on metastasis formation in the same experimental conditions, while the anticoagulant enoxaparin (1 mg/kg, subcutaneously (s.c.)) did not modify the antimetastatic action of dDAVP. In vitro, dDAVP had a strong inhibitory effect on F3II cell colony formation.. dDAVP interferes with early metastatic disease, and direct association of this effect with hemostatic mechanisms is unlikely.

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Deamino Arginine Vasopressin; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Lung Neoplasms; Mice; Mice, Inbred BALB C; Tumor Burden

The purpose of this study was to clarify the underlying mechanism of vertiginous attacks in Ménière's disease (MD) while obtaining insight into water homeostasis in the inner ear using a new animal model. We conducted both histopathological and functional assessment of the vestibular system in the guinea-pig. In the first experiment, all animals were maintained 1 or 4 weeks after electrocauterization of the endolymphatic sac of the left ear and were given either saline or desmopressin (vasopressin type 2 receptor agonist). The temporal bones from both ears were harvested and the extent of endolymphatic hydrops was quantitatively assessed. In the second experiment, either 1 or 4 weeks after surgery, animals were assessed for balance disorders and nystagmus after the administration of saline or desmopressin. In the first experiment, the proportion of endolymphatic space in the cochlea and the saccule was significantly greater in ears that survived for 4 weeks after surgery and were given desmopressin compared with other groups. In the second experiment, all animals that underwent surgery and were given desmopressin showed spontaneous nystagmus and balance disorder, whereas all animals that had surgery but without desmopressin administration were asymptomatic. Our animal model induced severe endolymphatic hydrops in the cochlea and the saccule, and showed episodes of balance disorder along with spontaneous nystagmus. These findings suggest that administration of desmopressin can exacerbate endolymphatic hydrops because of acute V2 (vasopressin type 2 receptor)-mediated effects, and, when combined with endolymphathic sac dysfunction, can cause temporary vestibular abnormalities that are similar to the vertiginous attacks in patients with MD.

Topics: Animals; Deamino Arginine Vasopressin; Disease Models, Animal; Ear, Inner; Endolymphatic Hydrops; Guinea Pigs; Histocytochemistry; Meniere Disease; Nystagmus, Pathologic; Posture

Desmopressin (DDAVP), a synthetic peptide analog of vasopressin, is a safe antidiuretic and hemostatic compound that acts as a selective agonist for the vasopressin V2 membrane receptor. It is known that DDAVP can inhibit progression of residual metastatic cells and also improves chemotherapy effects in preclinical breast cancer models. Here, we explored the effects of DDAVP on tumor angiogenesis using the aggressive F3II mammary carcinoma in syngeneic Balb/c mice. Intravenous administration of the compound (2 μg/kg) markedly decreased vascularization of growing subcutaneous tumors, as well as inhibited the early angiogenic response around intradermal inoculation sites. In vitro studies confirmed the presence of vasopressin V2 receptors on F3II cells and a modest antiproliferative activity of DDAVP. Interestingly, conditioned media from F3II monolayers exposed to low doses of DDAVP (100 nM) significantly increased angiostatin formation in the presence of purified plasminogen. Such increase was associated with an enhancement of tumor-secreted urokinase-type plasminogen activator, suggesting the proteolytic conversion of plasminogen to angiostatin in vitro. Similar results were observed with the MCF-7 human breast carcinoma, a cell line known to express the vasopressin V2 receptor. No direct effects of DDAVP (100 nM–1 μM) were found on capillary-like tube formation by human microvascular cells HMVEC. Our studies showed that DDAVP induces anti-angiogenic effects that may be associated with the generation of angiostatin by tumor cells. Further preclinical studies with DDAVP and other vasopressin analogs are warranted to determine their potential in cancer management.

Topics: Angiogenesis Inhibitors; Angiostatins; Animals; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Deamino Arginine Vasopressin; Disease Models, Animal; Endothelial Cells; Female; Humans; Mice; Neovascularization, Pathologic; Proteolysis; Receptors, Vasopressin; Tumor Burden

Binding of vasopressin to its type 2 receptor in renal collecting ducts induces cAMP signaling, transcription and translocation of aquaporin (AQP)2 water channels to the plasma membrane, and water reabsorption from the prourine. Demeclocycline is currently used to treat hyponatremia in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Demeclocycline's mechanism of action, which is poorly understood, is studied here. In mouse cortical collecting duct (mpkCCD) cells, which exhibit deamino-8-D-arginine vasopressin (dDAVP)-dependent expression of endogenous AQP2, demeclocycline decreased AQP2 abundance and gene transcription but not its protein stability. Demeclocycline did not affect vasopressin type 2 receptor localization but decreased dDAVP-induced cAMP generation and the abundance of adenylate cyclase 3 and 5/6. The addition of exogenous cAMP partially corrected the demeclocycline effect. As in patients, demeclocycline increased urine volume, decreased urine osmolality, and reverted hyponatremia in an SIADH rat model. AQP2 and adenylate cyclase 5/6 abundances were reduced in the inner medulla but increased in the cortex and outer medulla, in the absence of any sign of toxicity. In conclusion, our in vitro and in vivo data indicate that demeclocycline mainly attenuates hyponatremia in SIADH by reducing adenylate cyclase 5/6 expression and, consequently, cAMP generation, AQP2 gene transcription, and AQP2 abundance in the renal inner medulla, coinciding with a reduced vasopressin escape response in other collecting duct segments.

Topics: Adenylyl Cyclases; Animals; Anti-Bacterial Agents; Aquaporin 2; Cells, Cultured; Cyclic AMP; Deamino Arginine Vasopressin; Demeclocycline; Disease Models, Animal; Hyponatremia; In Vitro Techniques; Inappropriate ADH Syndrome; Kidney Medulla; Male; Mice; Minocycline; Rats; Rats, Wistar; Vasopressins

Adenosine diphosphate (ADP)-receptor antagonists are widely used for thrombus prevention, although reversing their platelet dysfunction is difficult. This study evaluated the ability of desmopressin to reverse clopidogrel-induced platelet dysfunction. Sprague-Dawley rats received either clopidogrel (30 mg/kg) or placebo, followed 4 h later by saline or desmopressin (0.15, 0.3, or 0.6 μg/kg). Bleeding times and platelet aggregation studies were subsequently performed. A bleeding time >25 min was considered "prolonged." The median bleeding time for clopidogrel-exposed rats was 21 min, vs. 6 min for controls (p < 0.01). Progressively higher doses of 1-deamino-8-D-arginine vasopressin (DDAVP) were associated with a reduced number of rats with prolonged bleeding time (p = 0.001). Higher doses of DDAVP were also associated with a reduction in the median (IQR) bleeding time; 29 (13.5-30) min in rats receiving clopidogrel without DDAVP vs. 19 (12-28) min in rats receiving clopidogrel and 0.6 μg/kg DDAVP. The step-wise dosing of DDAVP resulted in a 54 % reduction in meeting the endpoint of prolonged bleeding time (OR 0.46; p = 0.025; 95 % CI 0.23-0.91). Platelet aggregation was observed in all control rats, but only some of those clopidogrel-treated rats who received 0.6 μg/kg DDAVP. In this model of an ADP-receptor antagonist, DDAVP results in partial reversal of clopidogrel-induced platelet dysfunction.

Topics: Animals; Antidiuretic Agents; Bleeding Time; Clopidogrel; Deamino Arginine Vasopressin; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Overdose; Hemostatics; Injections, Intravenous; Male; Platelet Aggregation; Platelet Aggregation Inhibitors; Prodrugs; Purinergic P2Y Receptor Antagonists; Pyridines; Random Allocation; Rats; Rats, Sprague-Dawley; Ticlopidine

In the present study, we aimed to elucidate the effects of chronic vasopressin administration on renal medullary oxygen levels.. Adult Sprague Dawley or vasopressin-deficient Brattleboro rats were treated with the vasopressin V2 receptor agonist, desmopressin (5 ng/h; 3d), or its vehicle via osmotic minipumps. Immunostaining for pimonidazole and the transcription factor HIF-1α (hypoxia-inducible factor-1α) were used to identify hypoxic areas. Activation of HIF-target gene expression following desmopressin treatment was studied by microarray analysis.. Pimonidazole staining was detected in the outer and inner medulla of desmopressin-treated rats, whereas staining in control animals was weak or absent. HIF-1α immunostaining demonstrated nuclear accumulation in the papilla of desmopressin-treated animals, whereas no staining was observed in the controls. Gene expression analysis revealed significant enrichment of HIF-target genes in the group of desmopressin-regulated gene products (P = 2.6*10(-21) ). Regulated products included insulin-like growth factor binding proteins 1 and 3, angiopoietin 2, fibronectin, cathepsin D, hexokinase 2 and cyclooxygenase 2.. Our results demonstrate that an activation of the renal urine concentrating mechanism by desmopressin causes renal medullary hypoxia and an upregulation of hypoxia-inducible gene expression.

Topics: Animals; Deamino Arginine Vasopressin; Disease Models, Animal; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Kidney Medulla; Nitroimidazoles; Oxygen; Rats; Rats, Brattleboro; Rats, Sprague-Dawley; Receptors, Vasopressin; Signal Transduction; Vasopressins

Quantitative trait locus mapping of chemical/inflammatory pain in the mouse identified the Avpr1a gene, which encodes the vasopressin-1A receptor (V1AR), as being responsible for strain-dependent pain sensitivity to formalin and capsaicin. A genetic association study in humans revealed the influence of a single nucleotide polymorphism (rs10877969) in AVPR1A on capsaicin pain levels, but only in male subjects reporting stress at the time of testing. The analgesic efficacy of the vasopressin analog desmopressin revealed a similar interaction between the drug and acute stress, as desmopressin inhibition of capsaicin pain was only observed in nonstressed subjects. Additional experiments in mice confirmed the male-specific interaction of V1AR and stress, leading to the conclusion that vasopressin activates endogenous analgesia mechanisms unless they have already been activated by stress. These findings represent, to the best of our knowledge, the first explicit demonstration of analgesic efficacy depending on the emotional state of the recipient, and illustrate the heuristic power of a bench-to-bedside-to-bench translational strategy.

Topics: Analgesics; Animals; Animals, Newborn; Capsaicin; Deamino Arginine Vasopressin; Disease Models, Animal; Female; Genetic Association Studies; Habituation, Psychophysiologic; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molecular Weight; Pain; Pain Measurement; Pain Threshold; Polymorphism, Single Nucleotide; Quantitative Trait Loci; Receptors, Vasopressin; Sex Factors; Stress, Psychological; Vasopressins

Vasopressin influences salt and water transport in renal epithelia. This is coordinated by the combined action of V2 receptor-mediated effects along distinct nephron segments. Modulation of NaCl reabsorption by vasopressin has been established in the loop of Henle, but its role in the distal convoluted tubule (DCT), an effective site for fine regulation of urinary electrolyte composition and the target for thiazide diuretics, is largely unknown. The Na+-Cl- cotransporter (NCC) of DCT is activated by luminal trafficking and phosphorylation at conserved NH2-terminal residues. Here, we demonstrate the effects of short-term vasopressin administration (30 min) on NCC activation in Brattleboro rats with central diabetes insipidus (DI) using the V2 receptor agonist desmopressin (dDAVP). The fraction of NCC abundance in the luminal plasma membrane was significantly increased upon dDAVP as shown by confocal microscopy, immunogold cytochemistry, and Western blot, suggesting increased apical trafficking of the transporter. Changes were paralleled by augmented phosphorylation of NCC as detected by antibodies against phospho-threonine and phospho-serine residues (2.5-fold increase at Thr53 and 1.4-fold increase at Ser71). dDAVP-induced phosphorylation of NCC, studied in tubular suspensions in the absence of systemic effects, was enhanced as well (1.7-fold increase at Ser71), which points to the direct mode of action of vasopressin in DCT. Changes were more pronounced in early (DCT1) than in late DCT as distinguished by the distribution of 11beta-hydroxysteroid dehydrogenase 2 in DCT2. These results suggest that the vasopressin-V(2) receptor-NCC signaling cascade is a novel effector system to adjust transepithelial NaCl reabsorption in DCT.

Topics: 11-beta-Hydroxysteroid Dehydrogenase Type 2; Animals; Antidiuretic Agents; Blotting, Western; Cell Membrane; Chlorides; Deamino Arginine Vasopressin; Diabetes Insipidus, Neurogenic; Disease Models, Animal; Immunohistochemistry; Kidney Tubules, Distal; Male; Microscopy, Confocal; Natriuresis; Phosphorylation; Protein Transport; Rats; Rats, Brattleboro; Rats, Wistar; Receptors, Drug; Receptors, Vasopressin; Sodium; Sodium Chloride Symporter Inhibitors; Solute Carrier Family 12, Member 3; Symporters; Time Factors; Up-Regulation

Although fragrances are often used in aromatherapy for the treatment of edema, few studies on their diuretic and/or antiedematous activities have been performed. In this study, the effects of four types of fragrant ingredients (d-limonene, piperitone, alpha-pinene, and cinnamaldehyde) were examined in a mouse model of fluid retention. The mice were loaded with water after treatment with desmopressin (an antidiuretic hormone). In addition, zingerone, a pungent component of ginger which is considered to be effective in the treatment of edema, was examined. Moreover, their effects were compared with those of furosemide, a representative diuretic. Among the five types of fragrant ingredients examined, all except for cinnamaldehyde increased the urine volume in the fluid retention mouse model when administered at a dose of 100 mg/kg. In particular, d-limonene and zingerone significantly increased the urine volume. Thus the effects of these two ingredients were further examined at lower doses of 10 and 30 mg/kg. d-Limonene significantly increased the urine volume in a dose-dependent manner. Zingerone resulted in a significant increase in the urine volume only at a dose of 30 mg/kg. In normal mice, d-limonene did not affect the urine volume at the same doses. In contrast, zingerone significantly increased the urine volume in normal mice at a dose of 30 mg/kg. Furosemide significantly increased the urine volume in both the fluid-retentive and normal mice. These results indicate that both d-limonene and zingerone exhibit diuretic actions; however, the former fragrance only exerted an action in the fluid-retentive state. This different action suggests that d-limonene might be promising for the treatment of edema.

Topics: Animals; Aromatherapy; Cyclohexenes; Deamino Arginine Vasopressin; Disease Models, Animal; Diuretics; Dose-Response Relationship, Drug; Edema; Furosemide; Guaiacol; Limonene; Male; Mice; Mice, Inbred Strains; Terpenes

Arginine vasopressin (AVP) enhances water reabsorption in the renal collecting duct by vasopressin V₂ receptor (V₂R)-mediated activation of adenylyl cyclase (AC), cAMP-promoted phosphorylation of aquaporin-2 (AQP2), and increased abundance of AQP2 on the apical membrane. Multiple isoforms of adenylate cyclase exist, and the roles of individual AC isoforms in water homeostasis are not well understood. Here, we found that levels of AC6 mRNA, the most highly expressed AC isoform in the inner medulla, inversely correlate with fluid intake. Moreover, mice lacking AC6 had lower levels of inner medullary cAMP, reduced abundance of phosphorylated AQP2 (at both serine-256 and serine-269), and lower urine osmolality than wild-type mice. Water deprivation or administration of the V₂R agonist dDAVP did not increase urine osmolality of AC6-deficient mice to the levels of wild-type mice. Furthermore, AC6-deficient mice lacked dDAVP-promoted inner medullary cAMP formation and phosphorylation of serine-269 and had attenuated increases in both phosphorylation of serine-256 and apical membrane AQP2 trafficking. In summary, AC6 expression determines inner medullary cAMP formation and AQP2 phosphorylation and trafficking, the absence of which causes nephrogenic diabetes insipidus.

Topics: Adenylyl Cyclases; Animals; Aquaporin 2; Arginine Vasopressin; Blotting, Western; Cyclic AMP; Deamino Arginine Vasopressin; Diabetes Insipidus, Nephrogenic; Disease Models, Animal; Kidney Medulla; Kidney Tubules, Collecting; Mice; Mice, Inbred Strains; Osmolar Concentration; Phosphorylation; Polymerase Chain Reaction; Random Allocation; RNA, Messenger; Sensitivity and Specificity; Water Deprivation; Water-Electrolyte Balance

In a state of chronic arginine vasopressin (AVP)-induced antidiuresis, the antidiuretic efficacy has been attenuated: a phenomenon known as "AVP escape". We compared the experimental SIADH rats with 1-deamino-8-D-AVP (dDAVP)-excess rats. The SIADH rats, but not the dDAVP-excess rats, showed a marked attenuation of urinary concentrating ability. This is closely associated with diminished up-regulation of aquaporin-2 (AQP-2) mRNA and protein expression. The following in vitro study clarified tonicity-response elements in the 5'-flanking region of AQP-2 gene. There are at least more than two hypertonicity-response elements, and a hypotonicity-response element resided at tonicity-response enhancer (TonE) (-570 to -560bp) in the AQP-2 gene. Hypotonicity directly reduced the cAMP-induced AQP-2 promoter activity by mediating JNK kinase. Reduction in transcriptional regulation of AQP-2 under hypotonic state may support the in vivo finding of AVP escape phenomenon in chronic AVP-induced antidiuresis.

Topics: Animals; Aquaporin 2; Arginine Vasopressin; Bucladesine; Deamino Arginine Vasopressin; Disease Models, Animal; Diuresis; Gene Expression Regulation; Genes, Reporter; Heart Failure; Inappropriate ADH Syndrome; Kidney; Luciferases; Promoter Regions, Genetic; Rats; RNA, Messenger; Water-Electrolyte Imbalance

In mammals, the hormonal regulation of water homeostasis is mediated by the aquaporin-2 water channel (Aqp2) of the collecting duct (CD). Vasopressin induces redistribution of Aqp2 from intracellular vesicles to the apical membrane of CD principal cells, accompanied by increased water permeability. Mutations of AQP2 gene in humans cause both recessive and dominant nephrogenic diabetes insipidus (NDI), a disease in which the kidney is unable to concentrate urine in response to vasopressin. In this study, we generated a line of mice with the distal COOH-terminal tail of the Aqp2 deleted (Aqp2(Delta230)), including the protein kinase A phosphorylation site (S256), but still retaining the putative apical localization signal (221-229) at the COOH-terminal. Mice heterozygous for the truncation appear normal. Homozygotes are viable to adulthood, with reduced urine concentrating capacity, increased urine output, decreased urine osmolality, and increased daily water consumption. Desmopressin increased urine osmolality in wild-type mice but had no effect on Aqp2(Delta230/Delta230) mice. Kidneys from affected mice showed CD and pelvis dilatation and papillary atrophy. By immunohistochemical and immunoblot analyses using antibody against the NH(2)-terminal region of the protein Aqp2(Delta230/Delta230) mice had a markedly reduced protein abundance. Expression of the truncated protein in MDCK cells was consistent with a small amount of functional expression but no stimulation. Thus we have generated a mouse model of NDI that may be useful in studying the physiology and potential therapy of this disease.

Topics: Animals; Aquaporin 2; Atrophy; Cell Line; Deamino Arginine Vasopressin; Diabetes Insipidus, Nephrogenic; Disease Models, Animal; Diuresis; Dogs; Drinking; Gene Deletion; Heterozygote; Homozygote; Kidney Concentrating Ability; Kidney Medulla; Kidney Pelvis; Kidney Tubules, Collecting; Mice; Mutation; Osmolar Concentration; Protein Structure, Tertiary

We previously reported that vasopressin deficient Brattleboro (BRAT) rats exhibit deficits in prepulse inhibition (PPI) of the startle reflex that are consistent with PPI deficits exhibited by patients with schizophrenia and other neuropsychiatric disorders. Preliminary evidence indicates that this may be the basis of a predictive model for antipsychotic drug efficacy. Here we report the effects of acute and chronic administration of established and putative antipsychotics on these PPI deficits. BRAT rats, compared to their derivative strain, Long Evans rats, exhibited significantly decreased PPI and startle habituation consistent with patients with schizophrenia and other neuropsychiatric disorders. The second generation antipsychotics, risperidone and clozapine as well as a neurotensin agonist (PD149163) increased BRAT rat PPI, whereas saline, the typical antipsychotic, haloperidol, and a vasopressin analog (1-desamino-D-arginine vasopressin) did not. Similar to their effects in humans, chronic administration of antipsychotic drugs produced stronger effects than acute administration. These results further support the BRAT rat as a model of sensorimotor gating deficits with predictive validity for antipsychotics. The model appears to be able to differentiate first generation from second generation antipsychotics, identify putative antipsychotics with novel mechanisms (i.e., peptides) and reasonably model the therapeutic time course of antipsychotic drugs in humans.

Topics: Analysis of Variance; Animals; Antipsychotic Agents; Arginine Vasopressin; Clozapine; Deamino Arginine Vasopressin; Disease Models, Animal; Drug Administration Schedule; Drug Evaluation, Preclinical; Habituation, Psychophysiologic; Haloperidol; Neural Inhibition; Neurotensin; Rats; Rats, Brattleboro; Rats, Long-Evans; Rats, Mutant Strains; Reflex, Startle; Risperidone; Schizophrenia; Statistics, Nonparametric

In antidiuresis, vasopressin (AVP) occupation of V2 receptors in renal collecting ducts activates adenylyl cyclase, resulting in increased intracellular cAMP levels, which activates protein kinase A (PKA). PKA phosphorylates both the cAMP responsive element binding protein, which induces aquaporin-2 (AQP2) transcription, and AQP2, which then is translocated to the apical membrane, allowing urine concentration. Lithium treatment often causes nephrogenic diabetes insipidus (NDI), which coincides with decreased AQP2 expression and which generally is ascribed to reduced adenylyl cyclase activity. However, the underlying mechanism by which lithium causes NDI is poorly understood. This study demonstrated that the mouse cortical collecting duct mpkCCD(c14) cells are a good model; the deamino-8 D-arginine vasopressin (dDAVP)-induced endogenous AQP2 expression and plasma membrane localization was time-dependently reduced by treatment with clinically relevant lithium concentrations. Lithium did not affect AQP2 stability but decreased its mRNA levels. Surprising, the effect of lithium was cAMP independent; it did not alter AVP-stimulated cAMP production or PKA-dependent phosphorylation of AQP2 or cAMP responsive element binding protein. In vivo, kidney tissue of rats with lithium-induced NDI indeed generated less dDAVP-induced cAMP than that of controls, but this could be due to elevated blood AVP levels in rats with lithium-induced NDI. Indeed, Brattleboro rats, which lack endogenous AVP, with clamped blood dDAVP levels, showed no difference in dDAVP-generated cAMP generation between kidneys of rats with lithium-induced NDI and control rats. In conclusion, the first proper cell model to study lithium-induced NDI was developed, and it was demonstrated that the lithium-induced downregulation of AQP2 and development of NDI occur independent of adenylyl cyclase activity in vitro and in vivo.

Topics: Adenylyl Cyclases; Animals; Aquaporin 2; Clone Cells; Deamino Arginine Vasopressin; Diabetes Insipidus, Nephrogenic; Disease Models, Animal; Down-Regulation; In Vitro Techniques; Kidney Tubules, Collecting; Lithium; Male; Mice; Rats; Rats, Brattleboro; Rats, Wistar

Several FDA-approved intravenous drugs are used to reduce surgical bleeding. This series of studies tested whether these drugs (aprotinin, desmopressin, tranexamic acid, epsilon-aminocaproic acid) could reduce bleeding due to traumatic injuries in two models of uncontrolled hemorrhage in rats. In the first phase of each study, a nonlethal tail bleeding model was used that incorporated limited fluid resuscitation (lactate Ringer's solution). Four doses of vehicle or the test substance were given successively with bleeding time and blood loss measured after each dose. In the second phase of each study, a lethal liver injury was produced by excising a section of the median lobe (approximately 0.8% of body weight) and an infusion of either vehicle or the test substance was immediately begun. This model included aggressive fluid resuscitation and a severe dilutional coagulopathy. Blood loss, survival time and mortality rate were recorded. Three studies were performed, testing each of the drugs singly and in combination. None of the drugs significantly reduced either bleeding time or blood loss in the tail bleeding model, nor were blood loss, survival time or mortality rate altered in the liver injury model. Taken together, these results suggest that these FDA-approved drugs, when used either singly or in combination, are not efficacious in these models of traumatic uncontrolled hemorrhage.

Topics: Aminocaproic Acid; Animals; Antifibrinolytic Agents; Aprotinin; Deamino Arginine Vasopressin; Disease Models, Animal; Drug Approval; Drug Therapy, Combination; Hemorrhage; Hemostatics; Infusions, Intravenous; Liver; Male; Rats; Rats, Sprague-Dawley; Survival Analysis; Tail; Tranexamic Acid; Wounds and Injuries

Central pontine myelinolysis (CPM) is a serious demyelination disease commonly associated with the rapid correction of hyponatremia. Although its pathogenesis remains unclear, the disruption of the blood-brain barrier (BBB) as a consequence of a rapid increase in serum sodium concentration is considered to play a critical role. Since glucocorticoids are known to influence BBB permeability and prevent its disruption as a result of hypertension or hyperosmolarity, we investigated whether dexamethasone (DEX) could protect against osmotic demyelination in an animal model of CPM. Hyponatremia was induced in rats by liquid diet feeding and dDAVP infusion. Seven days later, the animals' hyponatremia was rapidly corrected by injecting a bolus of hypertonic saline intraperitoneally. Rats subjected to this treatment displayed serious neurological impairment and 77% died within 5 days of rapid correction of their hyponatremia; demyelinative lesions were observed in various brain regions in these animals. On the other hand, rats that were treated with DEX (2 mg/kg, 0 and 6 h after hypertonic saline injection) exhibited minimal neurological impairment and all were alive after 5 days. Demyelinative lesions were rarely seen in the brains of DEX-treated rats. A marked extravasation of endogenous IgG was observed in the demyelinative lesions in the brains of rats that did not receive DEX, indicating disruption of the BBB, but was not observed in DEX-treated rats. Furthermore, Evans blue injection revealed a significant reduction in staining in the brains of DEX-treated rats (P < 0.05). These results indicate that early DEX treatment can prevent the BBB disruption that is caused by the rapid correction of hyponatremia and its associative demyelinative changes, and suggest that DEX might be effective in preventing CPM.

Topics: Animals; Blood-Brain Barrier; Brain; Deamino Arginine Vasopressin; Dexamethasone; Disease Models, Animal; Hypernatremia; Hyponatremia; Immunoglobulin G; Male; Myelinolysis, Central Pontine; Nerve Fibers, Myelinated; Rats; Rats, Sprague-Dawley; Saline Solution, Hypertonic; Water-Electrolyte Balance

Desmopressin (DDAVP) is a synthetic derivative of vasopressin with hemostatic and fibrinolytic properties that has been used during surgery in patients with bleeding disorders. Our aim was to investigate the effect of DDAVP on lung and lymph node metastatic cell colonization using a preclinical mouse mammary carcinoma model of subcutaneous tumor manipulation and surgical excision.. Female BALB/c mice bearing the highly aggressive F3II mammary carcinoma were subjected to repeated manipulations of primary tumors (0.5 kg/cm(2) during 2 min), followed (or not) by surgical excision. DDAVP was administered intravenously 30 min before and 24 h after each manipulation or surgery, at a dose of 2 microg/kg. At the end of the experiment, mice were sacrificed and necropsied.. Tumor manipulation induced dissemination to the axillary nodes and increased up to 6-fold the number of metastatic lung nodules. Perioperative treatment with DDAVP dramatically reduced regional metastasis. The incidence of lymph node involvement in manipulated animals was 12% with DDAVP and 87% without treatment (P < 0.02). Histopathological analysis of axillary nodes from DDAVP-treated animals showed sinusal histiocytosis and no evidence of cancer cells. Metastatic lung nodules were also reduced about 65% in animals treated with DDAVP (P = 0.026).. Our results suggest a potential clinical application of DDAVP in the management of breast cancer, as well as other aggressive solid tumors. DDAVP may be useful to reduce the risk of metastatic cell colonization both during and after surgical manipulation.

Topics: Animals; Axilla; Deamino Arginine Vasopressin; Disease Models, Animal; Hemostatics; Lung Neoplasms; Lymphatic Metastasis; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Time Factors

To evaluate the effects of desmopressin on pressure values inside the pelvis and ureter of the rat following acute obstruction.. By means of a microsurgical technique, 24 male Wistar rats were submitted to ureteral obstruction; pressure inside the ureter was recorded using a cannula and a micrometric glass column. In the treatment group (14 animals) 6 mg/kg of desmopressin were administered 30 min before the beginning of the experiment.. Rats pretreated with desmopressin showed a statistically significant reduction in mean intraureteral pressure following acute obstruction (p = 0.05).. In Wistar rats desmopressin demonstrated a powerful antidiuretic effect, reducing the intraureteral pressure. The experimental model is useful for a better understanding of physiopathology of renal colic and acute obstruction.

Topics: Acute Disease; Animals; Deamino Arginine Vasopressin; Disease Models, Animal; Male; Muscle Contraction; Pelvis; Pressure; Rats; Rats, Wistar; Renal Agents; Reproducibility of Results; Ureter; Ureteral Obstruction; Urodynamics

In animal models of the syndrome of inappropriate antidiuresis (SIADH), sustained administration of vasopressin and water results in free-water retention and progressive hyponatremia for several days, which is then followed by escape from the vasopressin-induced antidiuresis. With the onset of vasopressin escape, water excretion increases despite sustained administration of vasopressin, allowing water balance to be re-established and the serum sodium to be stabilized at a steady, albeit decreased, level. Studies from our laboratories have investigated whether this escape phenomenon can be attributed to altered regulation of aquaporin water channels. After four-day pre-treatment with 1-deamino-[8-D-arginine]-vasopressin (dDAVP) by osmotic minipump, rats were divided into control (continued dDAVP) and water-loaded (continued dDAVP plus a daily oral water load) groups. A significant increase in urine volume in the water-loaded rats was observed by the second day of water loading, indicating escape from antidiuresis. The onset of escape coincided temporally with a marked decrease in renal aquaporin-2 protein (measured by semi-quantitative immunoblotting), which began at day 2 and fell to 17% of control levels by day 3. In contrast, there was no decrease in the renal expression of aquaporins 1, 3, or 4. The marked suppression of whole kidney aquaporin-2 protein was accompanied by a concomitant suppression of whole kidney aquaporin-2 mRNA levels. Immunocytochemical localization and differential centrifugation studies demonstrated that trafficking of aquaporin-2 to the plasma membrane remained intact during vasopressin escape. Additional studies have indicated that the observed down-regulation of aquaporin-2 expression also occurs in the renal cortex as well as the inner and outer medullas, and can be reversed simply by water restriction despite maintenance of hyponatremia. Our results therefore suggest that escape from vasopressin-induced antidiuresis is attributable, at least in part, to a vasopressin-independent and osmolality-independent decrease in aquaporin-2 water channel expression in the renal collecting duct. Similar mechanisms likely contribute to the phenomenon of escape from antidiuresis seen clinically in patients with SIADH as well.

Topics: Animals; Aquaporin 2; Aquaporin 6; Aquaporins; Deamino Arginine Vasopressin; Disease Models, Animal; Diuresis; Drinking Behavior; Gene Expression Regulation; Inappropriate ADH Syndrome; Kidney; Male; Osmolar Concentration; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transcription, Genetic; Urine

The effect of pulse parameters (duty and frequency) in a constant direct current iontophoresis on the antidiuretic response (elevation in rat urinary osmotic pressure) of desmopressin acetate (DDAVP) was examined in diabetes insipidus rats. Although antidiuretic response was not affected by frequency, it was induced by a duty of more than 26% and prolonged with increasing duty. A positively relationship between dose and AUC, the area under the osmotic pressure-time curve, was confirmed by intravenous administration of DDAVP, and the AUC induced by the iontophoretic delivery increased with increasing duty. The voltage across rat skin required to maintain a constant current density was investigated. A higher voltage was initially applied rat skin in a higher duty. This was related the prolonged pharmacological response induced by iontophoresis.

Topics: Animals; Deamino Arginine Vasopressin; Diabetes Insipidus; Disease Models, Animal; Diuresis; Dose-Response Relationship, Drug; Electricity; Iontophoresis; Male; Rats; Rats, Wistar; Renal Agents; Skin Absorption

The effects of concentration, amperage and duration on the antidiuretic response induced by iontophoretic delivery of desmopressin acetate (DDAVP) were examined using a diabetes insipidus model in rats. A higher current density brought about a larger and longer antidiuretic response. Prolonged iontophoretic duration caused an overdose. Repeated short iontophoretic treatments with lower current density maintained a constant response with a short lag time and a rapid disappearance of pharmacological response immediately after cessation of the final treatment. This type of iontophoresis substantially reduced the inter-subject variability of response as compared to the response using an intranasal route of administration.

Topics: Administration, Cutaneous; Administration, Intranasal; Animals; Deamino Arginine Vasopressin; Diabetes Insipidus; Disease Models, Animal; Diuresis; Dose-Response Relationship, Drug; Drug Delivery Systems; Drug Overdose; Iontophoresis; Male; Rats; Rats, Wistar; Skin Absorption

Rats were infused with a selective agonist of vasopressin V2 receptors (1-desamino-D-arginine vasopressin; DDAVP) at two different doses (1 or 5 ng/h) and fed a liquid formula to produce both moderate (plasma [Na+] = 119-124 mmol/l) and severe (plasma [Na+] = 106-112 mmol/l) hyponatremia. Whole body water and electrolyte contents were analyzed after 1, 7, and 14 days of hyponatremia to assess the relative contributions from water retention and sodium depletion to hyponatremia of varying duration and severity. Body water of the hyponatremic rats was significantly increased over normonatremic control rats after 1 and 7 days; after 14 days, the 1 ng/h DDAVP-infused rats also had elevated body water, but the 5 ng/h DDAVP-infused rats returned to levels not significantly different from controls. Body Na+ and Cl- both decreased significantly after 1 day of hyponatremia, and these decreases were sustained for 14 days; measured decreases were significantly greater in the more hyponatremic rats compared with the less hyponatremic rats. Body K+ of the 1 ng/h DDAVP-infused rats was not different from control rats, but significant K+ decreases occurred in the 5 ng/h DDAVP-infused rats after 7 and 14 days. Analysis of the measured plasma Na+ concentrations vs. those predicted by the changes in body water and sodium showed that both water retention and sodium losses were necessary to predict the final plasma [Na+]. However, the relative contribution from each varied with the duration of induced hyponatremia: acutely, water retention was the major cause of decreased plasma [Na+], but sodium depletion became predominant with longer periods of sustained hyponatremia.

Topics: Animals; Body Water; Body Weight; Chlorides; Deamino Arginine Vasopressin; Disease Models, Animal; Hyponatremia; Inappropriate ADH Syndrome; Male; Potassium; Rats; Rats, Sprague-Dawley; Sodium

Mice of the RIIIS/J inbred strain have prolonged bleeding times (greater than 15 minutes) after experimental injury when compared with normal C57BL/6J mice (1.8 minutes) and other strains of mice. The prolonged bleeding time was accompanied by normal platelet counts. Platelet aggregation with collagen and agglutination with ristocetin were not significantly altered in RIIIS/J mice. Also, platelets from RIIIS/J mice had normal serotonin content and normal numbers of dense granules by electron microscopy. Thus, the bleeding abnormality is not due to platelet storage pool deficiency as has been found in several other mouse mutants. The activated partial thromboplastin time (APTT) which plasma from RIIIS/J mice was prolonged compared with normal mice, and factor VIII:C activity and von Willebrand antigen levels were one half to one third that of normal mouse plasma. Factor XI activity was also significantly deficient (levels at 42% to 64% of normal). Plasma of RIIIS/J mice contained the full complement of multimers of von Willebrand factor, although each multimer was lower in concentration compared with that in normal mice. Platelet alpha-granule von Willebrand antigen levels were similar to those of normal mice. The prolonged bleeding time of RIIIS/J mice was corrected by treatment with desmopressin. Heterozygous C57BL/6J x RIIIS/J F1 animals had low plasma von Willebrand antigen levels like the RIIIS/J parent and had variable bleeding times. Inheritance of the bleeding tendency was as an incomplete dominant, autosomal trait. These data indicate the RIIIS/J strain is a suitable animal model for type IA von Willebrand disease.

Topics: Animals; Antigens; Bleeding Time; Blood Platelets; Cytoplasmic Granules; Deamino Arginine Vasopressin; Disease Models, Animal; Factor VIII; Factor XI; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Microscopy, Electron; Partial Thromboplastin Time; Platelet Aggregation; Platelet Count; Serotonin; von Willebrand Diseases; von Willebrand Factor

1. The mechanism of the flushing, hypotension and tachycardia associated with i.v. administration of desGlyd(CH2)5D-Tyr(Et)VAVP (SK&F 101926; 25 micrograms kg-1) and the selective V2 antidiuretic agonist, desamino-8-D-arginine vasopressin (dDAVP; 3 micrograms kg-1) was studied in ketamine-anaesthetized rhesus monkeys. 2. The flushing associated with SK&F 101926 was reduced by pretreatment with a mast cell stabilizer and by repeated administration of peptide (within 2-4 weeks). A similar desensitization to dDAVP-associated flushing was observed on repeated administration. 3. Treatment with dDAVP also resulted in reduced SK&F 101926-associated flushing. 4. The hypotension associated with SK&F 101926 was not affected by pretreatment with a mast cell stabilizer. A similar degree of hypotension was observed with repeated administration of either SK&F 101926 or dDAVP. 5. The tachycardia associated with SK&F 101926 was reduced by pretreatment with a mast cell stabilizer or repeated administration of SK&F 101926. Repeated administration of dDAVP, however, resulted in an enhanced tachycardia. 6. Indomethacin (5 mg kg-1 i.v.) did not alter the flushing or the hypotension associated with the administration of either SK&F 101926 or dDAVP, but resulted in an enhanced tachycardia to SK&F 101926. 7. Administration of a selective V1 vasopressor antagonist did not result in flushing, hypotension or tachycardia. 8. It was concluded that the flushing response to vasopressin-like peptides in rhesus monkeys may be due to an action on mast cells, whereas the haemodynamic responses are not, but probably involve direct vasodilator actions.

Topics: Animals; Arginine Vasopressin; Blood Pressure; Deamino Arginine Vasopressin; Disease Models, Animal; Flushing; Heart Rate; Hemodynamics; Indomethacin; Macaca mulatta; Male

A new rat model of the Schwartz--Bartter syndrome was created by the administration of 1-deamino-8-D-arginine vasopressin together with a forced water intake. The treatment led to water retention, hypernatriuria, marked hyponatraemia (in 4-5 days) and severe cerebral oedema. These changes could be prevented by the simultaneous administration of [1-(beta-mercapto-beta, beta-cyclopentamethylene-propionic acid)- 2-o-ethyltyrosine-4-valine] arginine vasopressin. The observations indicate that this vasopressin antagonist analogue might be of use in the future as an effective drug against the Schwartz--Bartter syndrome.

Topics: Animals; Arginine Vasopressin; Deamino Arginine Vasopressin; Disease Models, Animal; Inappropriate ADH Syndrome; Male; Rats; Vasopressins; Water Intoxication

The systemic and renal effects of high partial ureteral obstruction were investigated in a new model of experimental hydronephrosis. The test group comprised 12 contralaterally nephrectomized growing male New Zealand rabbits. As compared to the pyelographic findings in 6 unilaterally nephrectomized control animals, the test group could be divided into partially obstructed but non-hydronephrotic and obstructed-hydronephrotic subgroups. Animals of all 3 groups were capable of increasing their weight during the first 2 postoperative months. The mean plasma creatinine concentration remained normal in the obstructed group and even hydronephrosis was compatible with a normal serum creatinine level. As studied during forced hypotonic expansion, the renal response to a vasopressin analogue was significantly different in all 3 animal groups. Reciprocal but less marked differences were noted in the animals' ability to retain water during this test. We conclude that in this experimental model the magnitude of the antidiuretic response is inversely related to the radiologically defined degree of obstruction.

Topics: Animals; Deamino Arginine Vasopressin; Disease Models, Animal; Diuresis; Hydronephrosis; Kidney; Kidney Concentrating Ability; Male; Nephrectomy; Osmolar Concentration; Rabbits; Radiography; Ureteral Obstruction

An experimental model of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) was developed using continuous subcutaneous infusions of arginine vasopressin (AVP) or 1-desamino-8-D-arginine vasopressin (DDAVP) in conscious unrestrained rats drinking 5% dextrose solution. Retention of both ingested water and endogenously generated free water from tissue catabolism was the primary determinant of hyponatremia using either AVP or DDAVP infusions. Natriuresis occurred transiently following water expansion but only slightly further lowered plasma [Na+]. Cessation of antidiuretic infusion resulted in free water excretion with correction of plasma [Na+]. Erythrocyte cell volume was significantly increased in hyponatremic animals and intracellular [K+] and [Na+] both decreased equivalently, consistent with dilution of intracellular fluid by retained water. This model of SIADH differs significantly from those previously described, in that escape from the hydroosmotic effect of AVP and DDAVP does not occur in the absence of high urinary flow rates. The observed results using this model suggest that the retained water in SIADH primarily resides intracellularly following isotonic equilibration of extracellular fluid volume.

Topics: Animals; Arginine Vasopressin; Body Water; Deamino Arginine Vasopressin; Disease Models, Animal; Erythrocyte Count; Hyponatremia; Inappropriate ADH Syndrome; Male; Potassium; Rats; Rats, Inbred Strains; Rodent Diseases; Sodium