Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pituitary adenylate cyclase activating polypeptide (PACAP) is a novel vasoactive intestinal peptide (VIP)-like peptide isolated from ovine hypothalami. The presence of PACAP-like immunoreactivity was recently demonstrated in nerve cell bodies of sensory ganglia in the rat. Since PACAP belongs to a large family of chemically related neuropeptides, we have, in the present study, tried to establish the synthesis of PACAP in neurons of sensory ganglia, using in situ hybridization with a 35S-labelled oligonucleotide probe complementary to PACAP mRNA. The expression of PACAP was compared to that of calcitonin gene-related peptide (CGRP) using a radiolabelled CGRP oligonucleotide probe. The PACAP probe labelled small to medium-sized neurons in the trigeminal ganglion and dorsal root ganglia at different levels, indicating the presence of PACAP mRNA. The CGRP probe labelled nerve cell bodies of varying size, outnumbering those labelled by the PACAP probe. In dorsal root ganglia, cells expressing PACAP constituted c. 10% and those expressing CGRP 46% of the total number of nerve cell bodies. Expression of PACAP was seen in a small subpopulation of cells expressing CGRP. We conclude that PACAP is synthesized in a subpopulation of neurons of sensory ganglia in the rat. Therefore, the recently described effects of PACAP--cutaneous vasodilation, potentiation of oedema formation and depression of nociceptive spinal reflexes--may be physiological and related to neurogenic inflammation and modulation of pain transmission.
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PMID:Pituitary adenylate cyclase activating polypeptide expression in sensory neurons. 789 55

The effects of pituitary adenylate cyclase activating polypeptide (PACAP) on the cardiovascular system were examined. When PACAP-38 (270 or 420 pmol/kg body weight) was administered intravenously to the anesthetized dogs, both mean arterial pressure and left ventricular systolic pressure increased within 2 min after a temporal depression. Pulmonary arterial systolic pressure increased promptly. These hemodynamic values and heart rates (HR) 5 min after injection were significantly higher than the corresponding values in physiological saline injected dogs, and some effects were still sustained over 15 min. Cardiac output and stroke volume also increased and the values at 5 min were significantly higher than those in controls. The high dose of PACAP-38 (420 pmol/kg) evoked greater responses than those induced by the low dose (270 pmol/kg). Plasma adrenaline, but neither noradrenaline nor dopamine concentration significantly increased 15 min after injection of 420 pmol/kg PACAP-38. Moreover, PACAP-38 clearly stimulated cyclic AMP production in rat cardiac myocytes with EC50 of 1.5 x 10(-9) M and plasma cAMP levels significantly and dose-dependently increased in dogs 5 min after administration. These results first demonstrated that PACAP has inotropic and chronotropic actions on the heart possibly by a direct stimulation of adenylate cyclase in cardiac myocytes and also that the cardiovascular functions may be possibly modified by an evoked adrenaline secretion in vivo.
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PMID:Effects of pituitary adenylate cyclase activating polypeptide (PACAP) on the cardiovascular system. 790 74

We investigated the effect of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) on synaptic transmission in rat hippocampal slices using extracellular recordings. Brief bath application of PACAP-38 induced a long-lasting depression of transmission at the Schaffer collateral-CA1 synapse while at the same time causing enhancement of the perforant path-granule cell synapse in the dentate gyrus. Depression at the CA1 synapse was not occluded by low frequency-induced long-term depression (LTD), nor was enhancement at the granule cell synapse blocked by previous high frequency-induced long-term potentiation (LTP). Both actions of PACAP-38 could be elicited in the presence of an N-methyl-D-aspartate (NMDA) receptor antagonist, or in the presence of inhibitors of cyclic AMP- or Ca2+-dependent protein kinases, suggesting a novel mechanism of synaptic modulation.
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PMID:Differential alteration of hippocampal synaptic strength induced by pituitary adenylate cyclase activating polypeptide-38 (PACAP-38). 912 96

Pituitary adenylate cyclase-activating polypeptide (PACAP-38) is a member of the vasointestinal polypeptide (VIP)/secretin/glucagon family of neuropeptides for which neuroregulatory functions have been postulated. PACAP-38 receptors are expressed in different brain regions, including hippocampus. In this study, we examined the dose-dependent effects of PACAP-38 on the excitatory postsynaptic field potential (fEPSP) evoked at the Schaffer collateral-CA1 synapse in rat hippocampal slices. Bath application of low dose (0.05 nM) of PACAP-38 induced long-lasting facilitation of the fEPSP. This enhancement was blocked by the cholinergic receptor antagonist atropine and partially by the NMDA receptor antagonist 2-amino-5-phosphonovalerate (APV) and therefore, shares a common mechanism with LTP. In contrast, a high dose (1 microM) of PACAP-38 induced a persistent depression of the fEPSP that was not blocked by antagonists of cholinergic receptors (i.e., atropine and mecamylamine), adenosine receptors (i.e., DCPCX), or glutamatergic NMDA receptors (APV). Intermediate doses (0.1-0.5 microM) of PACAP-38 produced an initial decrease of the fEPSP followed by an enhancement. This decrease was not blocked by atropine whereas the facilitation was. These results show that PACAP-38 modulates CA1 synaptic transmission in a dose-dependent manner and that the peptide interacts with cholinergic and glutamatergic systems.
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PMID:Differential effects of PACAP-38 on synaptic responses in rat hippocampal CA1 region. 1158 73

Abstract Activation of potassium (K(+)) currents plays a critical role in the control of programmed cell death. Because pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to inhibit the apoptotic cascade in the cerebellar cortex during development, we have investigated the effect of PACAP on K(+) currents in cultured cerebellar granule cells using the patch-clamp technique in the whole-cell configuration. Two types of outward K(+) currents, a transient K(+) current (I(A)) and a delayed rectifier K(+) current (I(K)) were characterized using two different voltage protocols and specific inhibitors of K(+) channels. Application of PACAP induced a reversible reduction of the I(K) amplitude, but did not affect I(A), while the PACAP-related peptide vasoactive intestinal polypeptide had no effect on either types of K(+) currents. Repeated applications of PACAP induced gradual attenuation of the electrophysiological response. In the presence of guanosine 5'-[gammathio]triphosphate (GTPgammaS), PACAP provoked a marked and irreversible I(K) depression, whereas cell dialysis with guanosine 5'-[betathio]diphosphate GDPbetaS totally abolished the effect of PACAP. Pre-treatment of the cells with pertussis toxin did not modify the effect of PACAP on I(K). In contrast, cholera toxin suppressed the PACAP-induced inhibition of I(K). Exposure of granule cells to dibutyryl cyclic adenosine monophosphate (dbcAMP) mimicked the inhibitory effect of PACAP on I(K). Addition of the specific protein kinase A inhibitor H89 in the patch pipette solution prevented the reduction of I(K) induced by both PACAP and dbcAMP. PACAP provoked a sustained increase of the resting membrane potential in cerebellar granule cells cultured either in high or low KCl-containing medium, and this long-term depolarizing effect of PACAP was mimicked by the I(K) specific blocker tetraethylammonium chloride (TEA). In addition, pre-incubation of granule cells with TEA suppressed the effect of PACAP on resting membrane potential. TEA mimicked the neuroprotective effect of PACAP against ethanol-induced apoptotic cell death, and the increase of caspase-3 activity observed after exposure of granule cells to ethanol was also significantly inhibited by TEA. Taken together, the present results demonstrate that, in rat cerebellar granule cells, PACAP reduces the delayed outward rectifier K(+) current by activating a type 1 PACAP (PAC1) receptor coupled to the adenylyl cyclase/protein kinase A pathway through a cholera toxin-sensitive Gs protein. Our data also show that PACAP and TEA induce long-term depolarization of the resting membrane potential, promote cell survival and inhibit caspase-3 activity, suggesting that PACAP-evoked inhibition of I(K) contributes to the anti-apoptotic effect of the peptide on cerebellar granule cells.
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PMID:PACAP inhibits delayed rectifier potassium current via a cAMP/PKA transduction pathway: evidence for the involvement of I k in the anti-apoptotic action of PACAP. 1506 41

At CA1 synapses, activation of NMDA receptors (NMDARs) is required for the induction of both long-term potentiation and depression. The basal level of activity of these receptors is controlled by converging cell signals from G-protein-coupled receptors and receptor tyrosine kinases. Pituitary adenylate cyclase activating peptide (PACAP) is implicated in the regulation of synaptic plasticity because it enhances NMDAR responses by stimulating Galphas-coupled receptors and protein kinase A (Yaka et al., 2003). However, the major hippocampal PACAP1 receptor (PAC1R) also signals via Galphaq subunits and protein kinase C (PKC). In CA1 neurons, we showed that PACAP38 (1 nM) enhanced synaptic NMDA, and evoked NMDAR, currents in isolated CA1 neurons via activation of the PAC1R, Galphaq, and PKC. The signaling was blocked by intracellular applications of the Src inhibitory peptide Src(40-58). Immunoblots confirmed that PACAP38 biochemically activates Src. A Galphaq pathway is responsible for this Src-dependent PACAP enhancement because it was attenuated in mice lacking expression of phospholipase C beta1, it was blocked by preventing elevations in intracellular Ca2+, and it was eliminated by inhibiting either PKC or cell adhesion kinase beta [CAKbeta or Pyk2 (proline rich tyrosine kinase 2)]. Peptides that mimic the binding sites for either Fyn or Src on receptor for activated C kinase-1 (RACK1) also enhanced NMDAR in CA1 neurons, but their effects were blocked by Src(40-58), implying that Src is the ultimate regulator of NMDARs. RACK1 serves as a hub for PKC, Fyn, and Src and facilitates the regulation of basal NMDAR activity in CA1 hippocampal neurons.
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PMID:Modulation of NMDA receptors by pituitary adenylate cyclase activating peptide in CA1 neurons requires G alpha q, protein kinase C, and activation of Src. 1633 32

The neurotrophins-nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT-3 and NT-4-represent a family of proteins essential for neuronal survival and plasticity. Each neurotrophin can signal through two different transmembrane receptors, Trk receptor tyrosine kinases and the p75 neurotrophin receptor, the first member of the TNF receptor superfamily. Neurotrophic factors play an important role in neurodegenerative diseases, as well as neuropsychiatric disorders such as depression, bipolar disease and eating disorders. Indeed, a number of approaches have been taken to use neurotrophins to treat Alzheimer's dementia, amyotrophic lateral sclerosis and peripheral sensory neuropathy. However, many of these clinical trails have failed, due to problems in delivery and unforeseen side effects of neurotrophic factors. An alternative approach is to use ligands in the G protein-coupled receptor (GPCR) family to transactivate trophic activities. We have discovered that treatment with adenosine, a neuromodulator that acts through G protein-coupled receptors, is capable of activating Trk tyrosine kinase receptors. Transactivation of neurotrophic receptors by GPCR ligands raise the possibility that small molecules may be used to elicit neurotrophic effects for the treatment of neurodegenerative diseases. This approach would allow for selective targeting of neurons that express specific G protein-coupled receptors and trophic factor receptors. GPCRs transduce information provided by extracellular signals to modulate synaptic activity and neurotransmission. In addition to the classical G protein signalling, GPCR ligands also activate receptor tyrosine kinases (RTK), including neurotrophin receptors. Activation of Trk neurotrophin receptors can occur by GPCR ligands in the absence of neurotrophins. Adenosine and PACAP (pituitary adenylate cyclase activating polypeptide) induce Trk activation specifically through their respective GPCRs to promote cell survival. Transactivation of Trks by GPCRs has emerged as a new theme in the biology of neurotrophin function. Although the precise role of transactivation is unknown, one possibility is that it adds a safety factor that might protect neurons from death in the absence of neurotrophins. Abnormal activity of the neurotrophin system has been implicated in several psychiatric and neurobiological illnesses. However, the lack of knowledge about the precise site of neurotrophin dysfunction has compromised the ability to improve the efficacy and the safety of drugs used in treatment modalities. If small-molecule GPCR ligands can ameliorate neuronal cell loss through Trk, transactivation may offer a new strategy for promoting trophic effects during neurodegeneration.
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PMID:Promoting neurotrophic effects by GPCR ligands. 1680 30

Extensive work has shown that activation of the cAMP-dependent protein kinase A (PKA) is crucial for long-term depression (LTD) of synaptic transmission in the hippocampus, a phenomenon that is thought to be involved in memory formation. Here we studied the role of an alternative target of cAMP, the exchange protein factor directly activated by cyclic AMP (Epac). We show that pharmacological activation of Epac by the selective agonist 8-(4-chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT) induces LTD in the CA1 region. Paired-pulse facilitation of synaptic responses remained unchanged after induction of this LTD, suggesting that it depended on postsynaptic mechanisms. The 8-pCPT-induced LTD was blocked by the Epac signalling inhibitor brefeldin-A (BFA), Rap-1 antagonist geranylgeranyltransferase inhibitor (GGTI) and p38 mitogen activated protein kinase (P38-MAPK) inhibitor SB203580. This indicated a direct involvement of Epac in this form of LTD. As for other forms of LTD, a mimetic peptide of the PSD-95/Disc-large/ZO-1 homology (PDZ) ligand motif of the AMPA receptor subunit GluR2 blocked the Epac-LTD, suggesting involvement of PDZ protein interaction. The Epac-LTD also depended on mobilization of intracellular Ca(2+), proteasome activity and mRNA translation, but not transcription, as it was inhibited by thapsigargin, lactacystin and anisomycin, but not actinomycin-D, respectively. Finally, we found that the pituitary adenylate cyclase activating polypeptide (PACAP) can induce an LTD that was mutually occluded by the Epac-LTD and blocked by BFA or SB203580, suggesting that the Epac-LTD could be mobilized by stimulation of PACAP receptors. Altogether these results provided evidence for a new form of hippocampal LTD.
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PMID:Epac mediates PACAP-dependent long-term depression in the hippocampus. 1956 45

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with pleiotropic functions. We report here that PACAP-deficient (PACAP-/-) mice showed increased immobility in a forced swimming test, which was reduced by the antidepressant desipramine, to a similar extent as in wild-type mice. The atypical antipsychotic risperidone and the selective serotonin (5-HT)(2) antagonist ritanserin normalized the depression-like behavior in PACAP-/- mice. The 5-HT(2) agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine-induced 5-HT syndrome was exaggerated in PACAP-/- mice, which suggests a 5-HT(2)-receptor-dependent mechanism in the depression-like behavior. The circadian rhythm of plasma corticosterone and body core temperature was significantly flattened in the mutants. mRNA expression of glucocorticoid receptor was reduced in the mutant hippocampus. The present results suggest that alterations in PACAP signaling might contribute to the pathogenesis of certain depressive conditions amenable to atypical antipsychotic drugs.
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PMID:Depression-like behavior in the forced swimming test in PACAP-deficient mice: amelioration by the atypical antipsychotic risperidone. 1945 81

Pituitary adenylate cyclase-activating polypeptide (PACAP, ADCYAP1: adenylate cyclase-activating polypeptide 1) is a neuropeptide with neurotransmission modulating activity. The associations of the PACAP gene with schizophrenia and hippocampal volume have been reported. We recently reported depression-like behavior in the forced swimming test in PACAP deficient mice. Here we examined a possible association between the PACAP gene and major depressive disorder (MDD) in 637 patients and 967 controls and found that a genetic variant in the gene was associated with MDD. The present results suggest that PACAP signaling might contribute to the pathogenesis of MDD.
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PMID:Possible association between the pituitary adenylate cyclase-activating polypeptide (PACAP) gene and major depressive disorder. 1991 36


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