biie-0246 and Disease-Models--Animal

Neuropeptide Y (NPY), the prototypical member of the NPY-like peptide family, antagonizes behavioral consequences of stress through actions within the brain. This was initially indicated by microinjection studies with NPY receptor ligands, suggesting that NPY Y1 receptors mediate the anti-stress effects of NPY. Behavioral anti-stress actions of NPY are note-worthy in that 1) their magnitude surpasses that of other endogenous compounds; 2) they are produced across a wide range of animal models, normally thought to reflect different aspects of emotionality. These findings suggest that NPY acts with a high potency on a common core mechanism of emotionality and behavioral stress responses. This hypothesis is supported by behavioral studies in genetically modified animals. Increased emotionality, as well as increased alcohol intake, has been reported in mice with a homologous recombination knockout of the preproNPY gene. More detailed studies have been made possible by a transgenic rat system, in which NPY is selectively overexpressed within the hippocampus. These subjects display no overt phenotype under baseline conditions and have a normal endocrine stress response, but lack behavioral responses to stress. These findings point to the potential of the NPY system for developing novel pharmacological treatments of stress-related disorders, including anxiety and depression. Recent data additionally point to a role of NPY in the regulation of alcohol intake, and alcohol dependence emerges as a novel potential indication for compounds targeting the NPY system.

Topics: Alcoholism; Animals; Anxiety; Arginine; Behavior, Animal; Benzazepines; Brain; Depression; Disease Models, Animal; DNA-Binding Proteins; Gene Expression; Genetic Heterogeneity; Humans; Neuropeptide Y; Receptors, Neuropeptide Y; Stress, Physiological

Memory is the ability to store, retrieve and use information that requires a progressive time-dependent stabilization process known as consolidation to be established. The hippocampus is essential for processing all the information that forms memory, especially spatial memory. Neuropeptide Y (NPY) affects memory, so in this study we investigated the participation and recruitment of NPY receptors during spatial memory consolidation in rats. Using the water maze test, we show that NPY (1 pmol) injected into the dorsal hippocampus impaired memory consolidation and that previous restraint stress (30 min) potentiates NPY effects, i.e. further impaired memory consolidation. Using selective antagonists for NPY Y

Topics: Animals; Arginine; Behavior, Animal; Benzazepines; Disease Models, Animal; Male; Memory Disorders; Neuropeptide Y; Rats; Rats, Wistar; Receptors, Neuropeptide Y; Restraint, Physical; Spatial Memory; Stress, Psychological

Albuminuria is an independent risk factor for the progression to end-stage kidney failure, cardiovascular morbidity, and premature death. As such, discovering signaling pathways that modulate albuminuria is desirable. Here, we studied the transcriptomes of podocytes, key cells in the prevention of albuminuria, under diabetic conditions. We found that

Topics: Albuminuria; Animals; Arginine; Benzazepines; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Disease Models, Animal; Down-Regulation; Doxorubicin; Humans; Insulin; Kidney Diseases; Kidney Glomerulus; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Neuropeptide Y; Podocytes; Proteomics; Receptors, Neuropeptide Y; Signal Transduction

Administration of dextran sodium sulfate (DSS) to rodents at varying concentrations and exposure times is commonly used to model human inflammatory bowel disease (IBD). Currently, the criteria used to assess IBD-like pathology seldom include surrogate measures of visceral pain. Thus, we sought to standardize the model and then identify surrogate measures to assess effects on visceral pain. We used various 4% DSS protocols and evaluated effects on weight loss, colon pathology, biochemistry, RNA signature, and open field behavior. We then tested the therapeutic potential of NPY Y1 and/or Y2 receptor inhibition for the treatment of IBD pathology using this expanded panel of outcome measures. DSS caused weight loss and colon shrinkage, increased colon NPY and inflammatory cytokine expression, altered behaviors in the open field and induced a distinct gene metasignature that significantly overlapped with that of human IBD patients. Inhibition of Y1 and/or Y2 receptors failed to improve gross colon pathology. Y1 antagonism significantly attenuated colon inflammatory cytokine expression without altering pain-associated behaviors while Y2 antagonism significantly inhibited pain-associated behaviors in spite of a limited effect on inflammatory markers. A protocol using 7 days of 4% DSS most closely modeled human IBD pathology. In this model, rearing behavior potentially represents a tool for evaluating visceral pain/discomfort that may be pharmacologically dissociable from other features of pathology. The finding that two different NPY receptor antagonists exhibited different efficacy profiles highlights the benefit of including a variety of outcome measures in IBD efficacy studies to most fully evaluate the therapeutic potential of experimental treatments.

Topics: Animals; Arginine; Benzazepines; Body Weight; Colitis; Dextran Sulfate; Disease Models, Animal; Female; Humans; Inflammatory Bowel Diseases; Male; Mice; Mice, Inbred C57BL; Receptors, Neuropeptide Y

Accumulated evidence suggests that neuropeptide Y (NPY) is involved in emotional disorders by acting on Y(1) and Y(2) receptors. This hypothesis is based on animal studies carried out in naïve normal animals but not in animal models of depression, including the olfactory bulbectomized (OBX) rat. The OBX rat produces a wide array of symptoms that mimic several aspects of human depression and anxiety disorders. In the present study, we aimed to investigate the effects of sustained (2 weeks) intracerebroventricular administration of NPY Y(1) and Y(2) agonists and antagonists in a battery of behavioral tests including the open field, forced swim test (FST) and social interaction (SI) tests in OBX rats. The levels of Y(1) and Y(2) receptors in the hippocampus and basolateral amygdala (BLA) were also evaluated. Treatment with the Y(1)-like receptor agonist, [Leu(31)Pro(34)]PYY, decreased both depressive- and anxiogenic-like behaviors. The Y(2) receptor antagonist, BIIE0246, decreased the immobility time in the FST in OBX animals and increased active contacts in the SI test in sham rats. The Y(2) agonist, PYY3-36, increased the immobility time in the FST in OBX rats. Additionally, increased levels of Y(2) receptor binding were quantified in the dorsal hippocampus and BLA in OBX rats. Taken together, the autoradiographic results add further evidence that the NPYergic system is altered in disturbed emotional states. Moreover, we demonstrate a differential role for NPY Y(1) and Y(2) receptors in emotional processes under control and challenged conditions. This article is part of a Special Issue entitled 'Anxiety and Depression'.

Topics: Amygdala; Analysis of Variance; Animals; Anxiety; Arginine; Autoradiography; Benzazepines; Depression; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Delivery Systems; Exploratory Behavior; Hippocampus; Interpersonal Relations; Male; Neuropeptide Y; Olfactory Bulb; Rats; Rats, Sprague-Dawley; Receptors, Neuropeptide Y; Swimming; Time Factors

Neuropeptide Y (NPY) has an important but still insufficiently defined role in pain modulation. We therefore examined the ability of NPY to modulate experimentally induced neuropathic pain by injecting it directly into dorsal root ganglion (DRG) immediately following spinal nerve ligation (SNL) injury. We have found that this application exacerbates pain-related behavior induced by SNL in a modality-specific fashion. When saline was injected after SNL, the expected increase in hyperalgesia responses to needle stimulation was present on the 8th postoperative day. When we injected NPY, hyperalgesic responses were increased in a manner similar to the SNL/saline group. To characterize NPY action, specific Y1 and Y2 antagonists were also delivered directly to DRG, which revealed that behavioral actions of NPY were abolished by Y2 receptor antagonist. We tested whether NPY effects were the result of its role in immunity by immunohistochemical staining for glial fibrillary acidic protein, in order to identify activation of DRG satellite cells and dorsal horn astrocytes. Exacerbation of pain-related behavior following NPY injection was accompanied by astrocyte activation in ipsilateral dorsal horn and with satellite cells activation in the DRG proximal to injury. This activation was reduced following Y2 receptor antagonist application. These findings indicate an important link between pain-related behavior and neuroimmune activation by NPY through its Y2 receptor.

Topics: Analysis of Variance; Animals; Arginine; Benzazepines; Disease Models, Animal; Dose-Response Relationship, Drug; Functional Laterality; Glial Fibrillary Acidic Protein; Hyperalgesia; Male; Motor Activity; Neuralgia; Neurons; Neuropeptide Y; Pain Measurement; Rats; Rats, Sprague-Dawley; Receptors, Neuropeptide Y; Rotarod Performance Test; Spinal Cord

The endopeptidase neprilysin (NEP) is a major amyloid-beta (Abeta) degrading enzyme and has been implicated in the pathogenesis of Alzheimer's disease. Because NEP cleaves substrates other than Abeta, we investigated the potential role of NEP-mediated processing of neuropeptides in the mechanisms of neuroprotection in vivo. Overexpression of NEP at low levels in transgenic (tg) mice affected primarily the levels of neuropeptide Y (NPY) compared with other neuropeptides. Ex vivo and in vivo studies in tg mice and in mice that received lentiviral vector injections showed that NEP cleaved NPY into C-terminal fragments (CTFs), whereas silencing NEP reduced NPY processing. Immunoblot and mass spectrometry analysis showed that NPY 21-36 and 31-36 were the most abundant fragments generated by NEP activity in vivo. Infusion of these NPY CTFs into the brains of APP (amyloid precursor protein) tg mice ameliorated the neurodegenerative pathology in this model. Moreover, the amidated NPY CTFs protected human neuronal cultures from the neurotoxic effects of Abeta. This study supports the possibility that the NPY CTFs generated during NEP-mediated proteolysis might exert neuroprotective effects in vivo. This function of NEP represents a unique example of a proteolytic enzyme with dual action, namely, degradation of Abeta as well as processing of NPY.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Arginine; Benzazepines; Cells, Cultured; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Gene Expression Regulation; Genetic Vectors; Humans; Mice; Mice, Transgenic; Neprilysin; Nerve Degeneration; Nerve Growth Factors; Neurons; Neuropeptide Y; Peptide Fragments; Receptors, Neuropeptide Y

A couple of papers indicate that patients with depression show a decrease in serum neuropeptide Y (NPY). To study the role of NPY in depression, we examined the effects of infusion of NPY into the hippocampus of learned helplessness (LH) rats (an animal model of depression). Infusion of NPY into the cerebral ventricle of LH rats showed antidepressant-like effects. Infusion of NPY into the CA3 region, but not the dentate gyrus (DG), produced antidepressant-like effects in the LH paradigm. Infusion of NPY did not affect locomotor activity or aversive learning ability. Coadministration of BIBO3304 (a Y1 receptor antagonist) with NPY to the CA3 region blocked the antidepressant-like effects of NPY, whereas coadministration of NPY with BIIE0246 (a Y2 receptor antagonist) to the CA3 region failed to block antidepressant-like effects. Furthermore, infusions of [Leu(31) Pro(34)]PYY (a Y1 and Y5 receptor agonist) alone and BIIE0246 alone into the CA3 region produced the antidepressant-like effects in LH rats. These results suggest that infusion of NPY into the CA3 region of hippocampus of LH rats produces antidepressant-like activity through Y1 receptors and attenuating effects through Y2 receptors.

Topics: Animals; Antidepressive Agents; Arginine; Avoidance Learning; Behavior, Animal; Benzazepines; Depression; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Exploratory Behavior; Helplessness, Learned; Hippocampus; Injections, Intraventricular; Male; Neuropeptide Y; Peptide YY; Rats; Rats, Sprague-Dawley; Reaction Time; Receptors, G-Protein-Coupled; Receptors, Neuropeptide

Neuropeptide Y is released together with norepinephrine from sympathetic nerve terminals during conditions of increased sympathetic activity. Neuropeptide Y is known to inhibit vagal activity, and accordingly, it might increase the risk for ventricular fibrillation during myocardial ischemia-reperfusion, with concomitant sympathetic stimulation. Counteracting the inhibiting effect of neuropeptide Y by the specific neuropeptide Y2 antagonist, BIIE0246, we expected occurrence of ventricular fibrillation in association with repeated periods of myocardial ischemia-reperfusion to decrease. The midleft anterior descending coronary artery was repeatedly occluded in 16 open-chest pigs. Eight pigs received BIIE0246, and the controls received the vehicle only. Ventricular fibrillation developed in 2 animals of the control group, but in 4 pigs receiving BIIE0246. Occurrence of ventricular fibrillation and ventricular tachycardia did not differ significantly between the 2 groups, and in association with repeated periods of regional myocardial ischemia, did not decline in pigs treated by the specific neuropeptide Y2-receptor antagonist BIIE0246.

Topics: Animals; Arginine; Benzazepines; Biomarkers; Blood Pressure; Body Temperature; Carbon Dioxide; Cardiac Output; Coronary Circulation; Coronary Stenosis; Disease Models, Animal; Female; Heart Rate; Hematocrit; Male; Myocardial Reperfusion; Myocardial Reperfusion Injury; Oxygen; Potassium; Receptors, Neuropeptide Y; Swine; Tachycardia, Ventricular; Ventricular Fibrillation

Evidence from genetically modified mice suggests a role for NPY in regulation of ethanol intake, but results of pharmacological studies have been more variable. We have previously shown that potentiation of NPY signaling through antagonism at NPY-Y2 receptors decreases operant responding for ethanol in Wistar rats without a history of dependence. Here, we examined the effects of Y2-antagonism in animals with a history of dependence induced by long-term intermittent exposure to ethanol vapor. The Y2-receptor antagonist BIIE0246 suppressed operant responding for ethanol (approximately 50%, p=0.01), at a dose (0.5 nmol i.c.v.) which was ineffective in subjects without a history of dependence. Responding for the ethanol-free control solution was unaffected. These data confirm that antagonism at central NPY-Y2 receptors selectively suppresses motivation to self-administer ethanol, and indicate that the NPY system is sensitized in animals with a history of dependence. This may render the NPY system, and Y2 receptors in particular, an attractive target for treatment of alcohol dependence.

Topics: Alcoholism; Animals; Arginine; Benzazepines; Brain; Brain Chemistry; Disease Models, Animal; Ethanol; Male; Neuropeptide Y; Rats; Rats, Wistar; Receptors, Neuropeptide Y; Self Administration

Prevention of nerve injury-induced tactile, but not thermal, hypersensitivity is achieved by ipsilateral lesions of the dorsal columns or lidocaine microinjection into the nucleus gracilis (n. gracilis). These and other data support the possibility that tactile hyperresponsiveness after nerve injury may be selectively mediated by a low-threshold myelinated fiber pathway to the n. gracilis. Here we identify a transmitter that might selectively mediate such injury-induced tactile hypersensitivity. Neuropeptide Y (NPY), normally not detected in the dorsal root ganglion (DRG) or in the n. gracilis of rats, became markedly upregulated at both sites and in the spinal cord after spinal nerve injury. Injury-induced NPY-IR occurred predominately in large-diameter DRG cells, and the NPY-IR in the n. gracilis was blocked by dorsal rhizotomy or dorsal column lesion. NPY microinjection into the n. gracilis of uninjured rats elicited reversible tactile, but not thermal, hypersensitivity only in the ipsilateral hindpaw. Administration of anti-NPY antiserum, but not control serum or preabsorbed serum, into the n. gracilis ipsilateral to nerve injury reversed tactile, but not thermal, hypersensitivity. Similarly, microinjection of the NPY antagonists NPY(18-36) and (R)-N-[[4-(aminocarbonylaminomethyl)-phenyl]methyl]-N2-(diphenylacetyl)-argininamide trifluoroacetate, into the n. gracilis ipsilateral to the injury reversed tactile, but not thermal, hypersensitivity. Antagonist administration into the contralateral n. gracilis had no effect on injury-induced hypersensitivity. These data suggest the selective mediation of nerve injury-induced tactile hypersensitivity by upregulated NPY via large fiber input to n. gracilis. Selective reversal of injury-induced tactile allodynia by NPY receptor antagonists would have significant implications for human neuropathic conditions.

Topics: Animals; Arginine; Benzazepines; Disease Models, Animal; Disease Progression; Ganglia, Spinal; Hyperalgesia; Immune Sera; Ligation; Lumbosacral Region; Male; Medulla Oblongata; Microinjections; Nerve Crush; Neuropeptide Y; Pain Measurement; Pain Threshold; Rats; Rats, Sprague-Dawley; Receptors, Neuropeptide Y; Rhizotomy; Spinal Cord; Spinal Nerves