Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuropeptide Y (NPY) has been implicated in antiepileptic action in different in vivo and in vitro epilepsy models in rats and mice. Both Y2 and Y5 receptors could mediate the seizure-suppressant effect of NPY. However, lack of selective ligands precluded previous studies from conclusively evaluating the role of Y5 receptors in anti-epileptiform action of NPY. In the present study, using the new highly selective Y5 receptor antagonist, CGP71683A, and agonist, [cPP]hPP, we show that the Y5 receptor subtype is centrally involved in NPY-induced suppression of spontaneous epileptiform (interictaform) bursting in the CA3 area of rat hippocampal slices. This novel finding underscores the importance of Y5 receptors as a potential target for future antiepileptic therapy, particularly, for interictal components of temporal lobe epilepsy.
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PMID:Neuropeptide Y Y5 receptors suppress in vitro spontaneous epileptiform bursting in the rat hippocampus. 1507 65

Gene expression profiles in several brain regions of adult male rats were evaluated following a d-amphetamine (AMPH) exposure paradigm previously established to produce AMPH neurotoxicity. Escalating doses of AMPH (5-30 mg/kg) were given over the course of 16 h per day in an 18 degrees C environment for 2 days. This paradigm produces neurotoxicity but eliminates or minimizes the hyperthermia and seizure activity that might influence gene expression in a manner unrelated to the neurotoxic effects of AMPH. The expression of 1185 genes was monitored in the striatum, parietal cortex, piriform cortex and posteriolateral cortical amygdaloid nucleus (PLCo) using cDNA array technology, and potentially significant changes were verified by RT-PCR. Gene expression was determined at time points after AMPH when neurodegeneration was beginning to appear (16 h) or maximal (64 h). Expression was also determined 14 days after AMPH to find long-term changes in gene expression that might be biomarkers of a neurotoxic event. In the parietal cortex there was a two-fold increase in neuropeptide Y precursor protein mRNA whereas nerve growth factor-induced receptor protein I-A and I-B mRNA decreased 50% at 16 h after the end of AMPH exposure. Although these changes in expression were not observed in the PLCo, insulin-like growth factor binding protein 1 mRNA was increased two-fold in the PLCo at 16 and 64 h after AMPH. Changes in gene expression in the cortical regions were all between 1.2- and 1.5-fold 14 days after AMPH but some of these changes, such as annexin V increases, may be relevant to neurotoxicity. Gene expression was not affected by more than 1.5-fold at the time points in the striatum, although 65% dopamine depletions occurred, but the plasma membrane-associated dopamine transporter and dopamine D2 receptor were decreased about 40% in the substantia nigra at 64 h and 14 days post-AMPH. Thus, the 2-day AMPH treatment produced a few changes in gene expression in the two-fold range at time points 16 h or more after exposure but the majority of expression changes were less than 1.5-fold of control. Nonetheless, some of these lesser fold-changes appeared to be relevant to the neurotoxic process.
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PMID:Selective changes in gene expression in cortical regions sensitive to amphetamine during the neurodegenerative process. 1518 10

Neuropeptide Y (NPY) in the central nervous system is a major regulator of food consumption and energy homeostasis. It also regulates blood pressure, induces anxiolysis, enhances memory retention, affects circadian rhythms and modulates hormone release. Five Y receptors (Y1, Y2, Y4, Y5 and Y6) are known to mediate the action of NPY and its two other family members, peptide YY (PYY) and pancreatic polypeptide (PP). Increased NPY signaling due to elevated NPY expression in the hypothalamus leads to the development of obesity and its related phenotypes, Type II diabetes and cardiovascular disease. Dysregulation in NPY signaling also causes alterations in bone formation, alcohol consumption and seizure susceptibility. The large number of Y receptors has made it difficult to delineate their individual contributions to these physiological processes. However, recent studies analysing NPY and Y receptor overexpressing and knockout models have started to unravel some of the different functions of these Y receptors. Particularly, the use of conditional knockout models has made it possible to pinpoint a specific function to an individual Y receptor in a particular location.
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PMID:NPY and Y receptors: lessons from transgenic and knockout models. 1533 71

Neuropeptide Y (NPY), a 36 amino-acid member of the pancreatic polypeptide family, has received considerable attention in recent years as an endogenous modulator of epileptic activity. Prominently expressed in brain regions involved in seizure generation and propagation, NPY can exert powerful effects on synaptic transmission. Here, we discuss the anti-epileptic actions of NPY and receptor subtypes responsible.
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PMID:Neuropeptide Y and epilepsy: recent progress, prospects and controversies. 1533 78

Neuropeptide Y (NPY) administered exogenously is anticonvulsant, and, NPY null mutant mice are more susceptible to kainate-induced seizures. In order to better understand the potential role of NPY in epileptogenesis, the present studies investigated the development of amygdala kindling, post-kindling seizure thresholds, and anticonvulsant effects of carbamazepine and levetiracetam in 129S6/SvEv NPY(+/+) and NPY(-/-) mice. In addition, susceptibility to pilocarpine- and kainate-induced seizures was compared in NPY(+/+) and (-/-) mice. The rate of amygdala kindling development did not differ in the NPY(-/-) and NPY(+/+) mice either when kindling stimuli were presented once daily for at least 20 days, or, 12 times daily for 2 days. However, during kindling development, the NPY(-/-) mice had higher seizure severity scores and longer afterdischarge durations than the NPY(+/+) mice. Post-kindling, the NPY(-/-) mice had markedly lower afterdischarge thresholds and longer afterdischarge durations than NPY (+/+) mice. Carbamazepine and levetiracetam increased the seizure thresholds of both NPY (-/-) and (+/+) mice. In addition, NPY (-/-) mice had lower thresholds for both kainate- and pilocarpine-induced seizures. The present results in amygdala kindling and chemical seizure models suggest that NPY may play a more prominent role in determining seizure thresholds and severity of seizures than in events leading to epileptogenesis. In addition, a lack of NPY does not appear to confer drug-resistance in that carbamazepine and levetiracetam were anticonvulsant in both wild type (WT) and NPY null mutant mice.
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PMID:Seizure susceptibility of neuropeptide-Y null mutant mice in amygdala kindling and chemical-induced seizure models. 1545 Oct 8

Neuropeptide Y inhibits neuronal excitability and seizures in various experimental models. This peptide delays kindling epileptogenesis but the receptors involved in this action are unknown. We have studied the role of Y5 receptors in kindling using the selective antagonist GW438014A (IC50=210 nM), a small heterocycle molecule that crosses the blood-brain barrier, and the selective peptide agonist Ala31Aib34 NPY (IC50=6.0 nM). Intraperitoneal injection of GW438014A (10 mg/kg), 30 min before the beginning of a rapid-kindling protocol, significantly accelerated the rate of kindling acquisition as compared to vehicle-injected rats. Thus, the number of electrical stimuli required to reach stages 3 and 4-5 of kindling were reduced by 50% and 25%, respectively. The average afterdischarge duration in the stimulated hippocampus was prolonged by 2-fold. Conversely, kindling rate was delayed by intracerebroventricular administration of 24 nmol Ala31Aib32 NPY. Thus, the number of stimuli necessary to reach stages 2 and 3 of kindling was increased by 3- and 4-fold, respectively. During the stimulation protocol (40 stimuli) none of the rats treated with the Y5 agonist showed stages 4-5 seizures. Twenty-four hours after the last kindling stimulation, thus during the re-test session, Y5 agonist- or antagonist-treated rats had stages 4-5 seizures as their controls. In rats treated with both the antagonist and the agonist, kindling rate was similar to vehicle-injected rats. These data indicate that Y5 receptors mediate inhibitory effects of NPY in kindling and display anticonvulsant rather then antiepileptogenic effects upon agonist stimulation.
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PMID:Neuropeptide Y Y5 receptors inhibit kindling acquisition in rats. 1558 17

Neuropeptide Y (NPY) prominently inhibits epileptic seizures in different animal models. The NPY receptors mediating this effect remain controversial partially due to lack of highly selective agonists and antagonists. To circumvent this problem, we used various NPY receptor knockout mice with the same genetic background and explored anti-epileptic action of NPY in vitro and in vivo. In Y2 (Y2-/-) and Y5 (Y5-/-) receptor knockouts, NPY partially inhibited 0 Mg2+-induced epileptiform activity in hippocampal slices. In contrast, in double knockouts (Y2Y5-/-), NPY had no effect, suggesting that in the hippocampus in vitro both receptors mediate anti-epileptiform action of NPY in an additive manner. Systemic kainate induced more severe seizures in Y5-/- and Y2Y5-/-, but not in Y2-/- mice, as compared to wild-type mice. Moreover, kainate seizures were aggravated by administration of the Y5 antagonist L-152,804 in wild-type mice. In Y5-/- mice, hippocampal kindling progressed faster, and afterdischarge durations were longer in amygdala, but not in hippocampus, as compared to wild-type controls. Taken together, these data suggest that, in mice, both Y2 and Y5 receptors regulate hippocampal seizures in vitro, while activation of Y5 receptors in extra-hippocampal regions reduces generalized seizures in vivo.
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PMID:Differential suppression of seizures via Y2 and Y5 neuropeptide Y receptors. 1597 11

Neuropeptide Y (NPY) is one of the most abundant and widely distributed neuropeptides in the mammalian central nervous system (CNS). An overview of the distribution of the G-protein coupled NPY receptor family (Y(1), Y(2), Y(4), Y(5) receptors) in the brain is described. The coexistence of NPY with other neurotransmitters and its wide distribution in several brain areas predict the high importance of NPY as a neuromodulator. Thus, the effect of NPY on the release of several neurotransmitters such as glutamate, gamma-aminobutyric acid (GABA), norepinephrine (NE), dopamine, somastotatin (SOM), serotonin (5-HT), nitric oxide (NO), growth hormone (GH) and corticotropin releasing factor (CRF) is reviewed. A neuroprotective role for NPY under physiological conditions and during hyperactivity such as epileptic-seizures has been suggested. We have shown previously that NPY inhibits glutamate release evoked from hippocampal nerve terminals and has a neuroprotective effect in rat organotypic hippocampal cultures exposed to an excitotoxic insult. Moreover, changes in NPY levels have been observed in different pathological conditions such as brain ischemia and neurodegenerative diseases (Huntington's, Alzheimer's and Parkinson's diseases). Taken together, these studies suggest that NPY and NPY receptors may represent pharmacological targets in different pathophysiological conditions in the CNS.
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PMID:The putative neuroprotective role of neuropeptide Y in the central nervous system. 1610 53

Neuropeptide Y (NPY) potently inhibits glutamate release and seizure activity in rodent hippocampus in vitro and in vivo, but the nature of the receptor(s) mediating this action is controversial. In hippocampal slices from rats and several wild-type mice, a Y2-preferring agonist mimicked, and the Y2-specific antagonist BIIE0246 blocked, the NPY-mediated inhibition both of glutamatergic transmission and of epileptiform discharges in two different slice models of temporal lobe epilepsy, stimulus train-induced bursting (STIB) and 0-Mg2+ bursting. Whereas Y5 receptor-preferring agonists had small but significant effects in vitro, they were blocked by BIIE0246, and a Y5 receptor-specific antagonist did not affect responses to any agonist tested in any preparation. In slices from mice, NPY was without effect on evoked potentials or in either of the two slice seizure models. In vivo, intrahippocampal injections of Y2- or Y5-preferring agonists inhibited seizures caused by intrahippocampal kainate, but again the Y5 agonist effects were insensitive to a Y5 antagonist. Neither Y2- nor Y5-preferring agonists affected kainate seizures in mice. A Y5-specific antagonist did not displace the binding of two different NPY ligands in WT or mice, whereas all NPY binding was eliminated in the mouse. Thus, we show that Y2 receptors alone mediate all the anti-excitatory actions of NPY seen in the hippocampus, whereas our findings do not support a role for Y5 receptors either in vitro or in vivo. The results suggest that agonists targeting the Y2 receptor may be useful anticonvulsants.
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PMID:The anti-epileptic actions of neuropeptide Y in the hippocampus are mediated by Y and not Y receptors. 1619 Aug 96

The mechanisms by which electroconvulsive therapy (ECT) causes its antidepressive effect are unknown. Because ECT requires repeated induction of electroconvulsive seizures, adaptive changes in the brain and regulation of gene expression, are likely to be the fundamental basis on which ECT acts. Neuropeptide Y (NPY) gene expression is increased after multiple electroconvulsive stimulations (ECS) and since it also has anticonvulsant and antidepressant properties, it has led to the hypothesis that the beneficial effect of ECT is mediated via its activation of NPY-dependent neurotransmission. We have therefore examined in detail the temporal profile of NPY gene expression, using in situ hybridisation histochemistry in the rat dentate gyrus and piriform cortex - two brain areas centrally involved in seizure regulation. NPY mRNA in both regions was found to increase gradually with the number of ECS, reaching a maximum (550-700%) after approximately 14 ECS where no further increase was achieved by additional ECS. A number of 14 ECS was also shown to exert anticonvulsant activity against kainic acid seizures. In the dentate gyrus, repeated ECS also caused a gradual, but smaller, increase in the expression of somatostatin (SS) - a neuropeptide that is co-localised with NPY and also has anticonvulsant effects. These results shows that NPYergic and, to a lesser extent, SSergic neurotransmission is activated by ECS and support the hypothesis that these neuropeptides could play a central role in the anticonvulsant and antidepressant effect of ECT.
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PMID:Accumulated increase in neuropeptide Y and somatostatin gene expression of the rat in response to repeated electroconvulsive stimulation. 1645 71


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