cyclic-gmp and Hemorrhage

Ferulic acid (FA) produces protective effects against cardiovascular dysfunctions. However, the mechanisms of FA is still not known. Here we examined the antithrombotic effects of FA and its potential mechanisms. Anticoagulation assays and platelet aggregation was evaluated in vitro and in vivo. Thromboxane B2 (TXB2), cyclic adenosine monophosphate(cAMP), and cyclic guanosine monophosphate (cGMP) was determined using enzyme immunoassay kits. Nitric oxide (NO) production was measured using the Griess reaction. Protein expression was detected by Western blotting analysis. Oral administration of FA prevented death caused by pulmonary thrombosis and prolonged the tail bleeding and clotting time in mice,while, it did not alter the coagulation parameters, including the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). In addition, FA (50-200 µM) dose-dependently inhibited platelet aggregation induced by various platelet agonists, including adenosine diphosphate (ADP), thrombin, collagen, arachidonic acid (AA), and U46619. Further, FA attenuated intracellular Ca(2)(+) mobilization and TXB2 production induced by the platelet agonists. FA increased the levels of cAMP and cGMP and phosphorylated vasodilator-stimulated phosphoprotein (VASP) while decreased phospho-MAPK (mitogen-activated protein kinase) and phosphodiesterase (PDE) in washed rat platelets, VASP is a substrate of cyclic nucleotide and PDE is an enzyme family responsible for hydrolysis of cAMP/cGMP. These results suggest that antithrombotic activities of FA may be regulated by inhibition of platelet aggregation, rather than through inhibiting the release of thromboplastin or formation of thrombin. The mechanism of this action may involve activation of cAMP and cGMP signaling.

Topics: Animals; Blood Coagulation; Calcium; Cell Adhesion Molecules; Coumaric Acids; Cyclic AMP; Cyclic GMP; Fibrinolytic Agents; Hemorrhage; Intracellular Space; Male; Mice; Microfilament Proteins; Mitogen-Activated Protein Kinases; Nitric Oxide; Phosphoproteins; Phosphoric Diester Hydrolases; Phosphorylation; Rats; Signal Transduction; Superoxides; Thrombosis; Thromboxane B2

It was investigated the intercommunication of the functional state of cyclic nucleotides (CN) system and morphofunctional states of lung and heart tissues and influence on these state of lipid peroxidation processes and adenylate cyclase system activity under development in organism of the hypoxic states of different genesis. Obtained dates testify that with the changes of cAMP and cGMP concentrations, and also with their ratio the level of hyperhydratation of air-blood and blood-tissue barriers under the used influence on the organism are closely correlated. Intercommunication of the cyclic nucleotides system functioning and tissues oxygen consumption at the used influences carries sufficiently difficult and ambiguous character. It was shown that exactly at blood loss in lung and heart tissues there were the parallel diminishing of concentrations both cAMP and cGMP. It is accepted to correlate with a favorable histological dynamics. Exactly under these conditions the correlation of CN concentrations is possible to consider balanced and sent to limitation of displays of unfavorable influence of blood loss on investigated tissues ultrastructure. So, there is a tissue specific and depending from the type of influence on the organism character of intercommunication of the functional state of cyclic nucleotides system and morphofunctional states of lung and heart tissues.

Topics: Adaptation, Physiological; Animals; Cyclic AMP; Cyclic GMP; Hemorrhage; Hypoxia; Lipid Peroxidation; Lung; Male; Myocardium; Nucleotides, Cyclic; Oxygen Consumption; Rats; Rats, Wistar

Intracranial aneurysmal rupture is the common cause of spontaneous subarachnoid haemorrhage (SAH). This haemorrhage is typically diffuse and located in extracerebral subarachnoid space in which main cerebral arterial branches are situated. The intimate and long-term contact of arterial wall and blood products in the closed space causes the cerebral vasospasm as a serious and frequent complication of SAH. It is connected with significant morbidity and mortality due to developing of focal cerebral ischaemia and subsequently cerebral infarction. The aim of our experimental research was to create the animal model of vasospasm using the femoral artery due to examination of reduced basic dilator activity cause in arterial wall after SAH. The important characteristic of major cerebral arteries is their localization in the closed subarachnoid space which enables their to have long-term contact with blood products after haemorrhage. Thirty six femoral arteries (FA) of eighteen female rats weighing about 300 g were used. In vivo, femoral arteries are microsurgically prepared in both inguinal regions in all rats. Eighteen arteries were encompassed by polytetrafluoroethylene (PTFE) material forming closed tube and autologous blood was injected in the tube around the arterial wall. Additional eighteen arteries, as a control group, were also put in PTFE tube but without exposing to the blood. All rats are left to live for eight days. Afterwards, rats were sacrificed and their arteries were in vitro examined including an isometric tension measurement and histological changes analysis. The tension was measured during application of vasoconstrictors and vasodilatators (nitric oxide, NO). FA exposed to periadventitial blood exhibit hyper reactivity to constrictors (KCl, phenylephrine, acetylcholine) compared to control group. It was also found that NO donor (sodium nitroprusside) diminished arterial spasm induced by blood and vasoconstrictors. In conclusion, FA can be used as a model for vasospasm correlating with cerebral vasospasm after SAH and therefore this model can be utilized in future experiments assessing cerebral vasospasm. The reduced basic dilator activity of spastic femoral artery is caused by an absence of gaseous messenger NO next to the arteries but not by diminished response vasculature to NO. Absence of NO after SAH probably causes the reduced basic dilator activity of cerebral arteries as well. The guanylate-cyclase level in the arterial wall is conseque

Topics: Adenomatous Polyposis Coli; Animals; Cyclic GMP; Femoral Artery; Hemorrhage; Loss of Heterozygosity; Microsatellite Repeats; Models, Animal; Nitric Oxide; Polytetrafluoroethylene; Rats; Subarachnoid Hemorrhage; Vasodilator Agents; Vasospasm, Intracranial

The intracellular second messenger, cyclic guanosine monophosphate (cGMP), a soluble guanylate cyclase (GC) product, is a primary mechanism for the transduction of a nitric oxide (NO)-initiated signal in the central nervous system. NO is produced from L-arginine by neuronal nitric oxide synthase (NOS), which is found in sympathetic preganglionic neurons of the intermediolateral cell column. This suggests the possibility that NO is a modulator of sympathetic nervous activity (SNA) through a cGMP-mediated mechanism. The aim of this study was to determine the effects of intrathecally injected membrane-permeant 8-bromo-cGMP and 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ), a selective inhibitor of the soluble form of GC, on arterial pressure in urethane anaesthetized (1.4 g kg(-1) I.P.) rats. The effects of intrathecal cGMP and ODQ on haemodynamic responses to haemorrhage were also investigated. Finally, L-arginine, the NO precursor, was also injected intrathecally, alone and in the presence of ODQ. Baseline mean arterial pressure (MAP) increased significantly after intrathecal 8-Br-cGMP injection (10 microl, 1, 3, 10, 30, 100 microm). A dose-effect relationship (1 microm to 100 microm) was also established (EC(50)=6.03 microm). During continuous haemorrhage, MAP was maintained in animals injected with 8-Br-cGMP, relative to the control group. Although no change in baseline MAP was observed as a result of intrathecal ODQ injection (10 microl, 100 mM), a greater rate of fall in MAP was observed during haemorrhage. Injecting L-arginine (10, 100, 1000 microm, 10 microl) showed a pressor effect that was consistent with the effect of the downstream messenger, cGMP. Furthermore, its pressor effect was blocked by ODQ pre-administration. The results indicate that cGMP increases blood pressure, and thus suggest that cGMP increases SNA. This supports the hypothesis that the sympathoexcitatory effects of spinal delivery of NO are mediated by a cGMP-dependent mechanism.

Topics: Anesthesia; Animals; Arginine; Blood Pressure; Cyclic GMP; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Guanylate Cyclase; Heart Rate; Hemorrhage; Injections, Spinal; Nitric Oxide; Oxadiazoles; Pressoreceptors; Quinoxalines; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Soluble Guanylyl Cyclase; Sympathetic Nervous System

Hemoglobin-based oxygen carriers (HBOCs) have been developed primarily for their oxygenating function and possible use as an alternative to red blood cells during surgery or after major trauma. However, their effect on hemostasis has not been studied extensively. We compared the effects on hemostasis of bovine-derived hemoglobin solution (HBOC-201) with gelatin solution and saline infusion in an experimental model of arterial thrombosis and bleeding. After anesthesia, the Folts model was constructed in 30 rabbits. The common carotid artery was exposed, and a 60% stenosis was induced. A compression injury of the artery was then produced, which triggered a series of cyclic episodes of thrombosis (cyclic flow reductions [CFRs]). After the number of baseline CFRs was counted, animals were assigned randomly to one of three groups (n = 10 each): saline (control), gelatin, or HBOC-201 solution. The effect of studied solutions was observed by recording the number of CFRs during another period and was compared with that of saline. Ear immersion bleeding time was recorded after each CFR period. Gelatin and HBOC-201 had similar effects, manifested by significantly decreased CFRs (from median of 7 to 1 and 6 to 1, respectively) and significantly lengthened bleeding time (from 88 to 98 s and 81 to 102 s, respectively; P < 0.05). Saline infusion had no significant effect on CFRs or bleeding time. HBOC-201 and gelatin had similar effects marked by a reduction in the arterial thrombosis rate and increased bleeding time in rabbits.. In a rabbit thrombosis and hemorrhagic model, a polymerized bovine-derived hemoglobin solution and a gelatin solution infusion decreased arterial thrombosis and lengthened bleeding time.

Topics: Animals; Bleeding Time; Blood Platelets; Blood Substitutes; Carotid Arteries; Carotid Artery Thrombosis; Carotid Stenosis; Cattle; Chemistry, Pharmaceutical; Cyclic GMP; Gelatin; Hemodynamics; Hemorrhage; Hemostasis; Male; Platelet Aggregation; Rabbits

Diaspirin cross-linked hemoglobin (DCLHb) is a hemoglobin-based therapeutic agent that produces significant cardiovascular effects, possibly due to its actions on vasoactive substances, such as endothelin (ET) and nitric oxide (NO). We have studied the modulation of cardiovascular effects of DCLHb by an NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), and an ETA-receptor antagonist, FR-139317, in hemorrhaged rats. Control rats resuscitated with vehicle [Ringer lactate (RL), 4 ml/kg iv] did not show any improvement in O2 consumption, base deficit, systemic hemodynamics, or regional blood flow after hemorrhage, and the rats survived for < 70 min. Administration of DCLHb (400 mg/kg iv) significantly improved O2 consumption, base deficit, systemic hemodynamics, and regional blood circulation after resuscitation, and the rats survived for > 120 min after hemorrhage. Plasma ET-1 and guanosine 3',5'-cyclic monophosphate (cGMP) concentrations increased after hemorrhage. DCLHb produced an increase in ET-1 and decreased cGMP concentrations in plasma. Pretreatment with L-NAME (10 mg/kg iv) or FR-139317 (4 mg/kg iv) attenuated the DCLHb-induced improvement in survival time, base deficit, systemic hemodynamics, and regional blood circulation. L-NAME (10 mg/kg iv) per se did not produce any resuscitative effect; therefore the NO mechanism may not be contributing toward the efficacy of DCLHb in hemorrhaged rats. However, FR-139317 attenuated the efficacy of DCLHb; therefore an increase in plasma ET-1 concentration by DCLHb may be contributing toward the efficacy of DCLHb in hemorrhage. Hemorrhage-induced increase in cGMP levels could be attenuated by L-NAME, but L-NAME was not effective in resuscitation of hemorrhaged rats, indicating a lack of role of NO in resuscitation. It is concluded that the ET mechanism is more important in the beneficial effect of DCLHb than the NO mechanism in hemorrhage.

Topics: Animals; Aspirin; Blood Substitutes; Cyclic GMP; Endothelin-1; Endothelins; Enzyme Inhibitors; Gases; Hemodynamics; Hemoglobins; Hemorrhage; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Oxygen; Oxygen Consumption; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Resuscitation; Survival Analysis

The effects of myoglobin on renal microcirculation were studied in anesthetized rats subjected to hemorrhagic hypotension. Capillary flow distribution was determined by allowing two dyes to circulate for 3 and 1 min, respectively, freezing the left kidney and quantifying the dye distribution in histological sections by analyzing the distances of regularly spaced test points to the next dye-labeled capillary. Control experiments showed 88% of distances to be < 12 microns in the cortex [medullary outer stripe (OS): 77%, inner stripe (IS): 93%] and no distance to be > 60 microns. Myoglobin induced disturbances in intrarenal perfusion with a significantly higher potency of (Fe2+)- as compared to (Fe3+)-myoglobin. With the reduced species, the fraction of distances > 60 microns increased to 54% in the cortex (OS: 69%; IS: 67%). L-NAME, an inhibitor of nitric oxide synthesis, induced similar defects of perfusion. The cGMP analogue 8-Br-cGMP was able to nearly completely prevent these effects. The results support the view that myoglobin when released during hemorrhagic hypotension impairs renal microcirculation supposedly by scavenging the endogenous relaxing factor nitric oxide.

Topics: Anesthesia, Intravenous; Animals; Cyclic GMP; Enzyme Inhibitors; Hemorrhage; Hypotension; Iron; Kidney; Male; Microcirculation; Myoglobin; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Rats; Rats, Wistar; Renal Circulation

Our purpose was to determine the effects of nitric oxide synthase inhibition on maternal and fetal health in the last third of pregnancy.. Pregnant rats were treated from gestational day 13 to day 19 or 20 with the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester, which was administered in the drinking water ad libitum. Control animals received the inactive enantiomer NG-nitro-D-arginine methyl ester or no treatment. Maternal blood pressure, blood chemistry studies, and placenta and pup size were determined. A separate group of rats received nitroprusside sodium in conjunction with NG-nitro-L-arginine methyl ester.. NG-nitro-L-arginine methyl ester caused a dose-dependent reduction in placenta and pup size. Amniotic fluid levels of cyclic guanosine monophosphate were significantly reduced at 0.1 mg/ml but not at higher doses. Hemorrhagic necrosis of fetal hind limbs occurred only with treatment with NG-nitro-L-arginine methyl ester and was prevented by coadministration of nitroprusside sodium. Maternal blood pressure and blood and urine chemistry studies were unaffected by NG-nitro-L-arginine methyl ester.. Chronic reductions of nitric oxide production in the last third of pregnancy result in significant intrauterine growth retardation and hemorrhagic disruptions of hind limbs. Maternal complications were minimal and did not mimic preeclampsia.

Topics: Amniotic Fluid; Animals; Arginine; Cyclic GMP; Dose-Response Relationship, Drug; Female; Fetal Diseases; Fetal Growth Retardation; Fetus; Hemorrhage; Hindlimb; Necrosis; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitroprusside; Placenta; Pregnancy; Pregnancy, Animal; Rats; Rats, Sprague-Dawley