Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of xenin 25, a peptide of the neurotensin/xenopsin family, were examined on the motility of the guinea pig jejunum and colon in vitro. In the jejunum, xenin induced a biphasic response: first a small relaxation and then a large contraction. In the colon, xenin induced relaxation. The tenia coli was contracted. Deletion or amidation of the C-terminal leucine inactivated xenin. A peptide sequence of 16 C-terminal amino acids was necessary to elicit a full response in the jejunum, whereas in the colon, the potencies of all fragments of xenin 25, including the 6 C-terminal amino acid sequence (xenin 6), were not significantly different from that of xenin 25. In the jejunum, contraction was abolished or reduced by tetrodotoxin, by atropine, by met-enkephalin, by antagonists to the tachykinin receptors NK1 and NK2 and by the P2-purinoceptor antagonist suramin. L-NNA, phentolamine, methysergide, hexamethonium and apamin had no effect. In the colon, all actions of xenin were tetrodotoxin-resistant; the potency of xenin to relax was reduced by apamin and suramin. The actions of xenin on small and large bowel were attenuated by the neurotensin receptor antagonist SR 48692. The xenin analog neurotensin was significantly less potent than xenin 25 in contracting the jejunum and more potent than xenin 25 in relaxing the colon. We conclude that xenin exerts excitatory effects on a neuronal subtype receptor in the jejunum, with participation of muscarinic, purinergic and tachykinin-related mechanisms. Xenin exerts relaxing effects on the colon by interaction with a myokinetic subtype receptor involving Ca(++)-dependent K+ channels and the P2-purinoceptor.
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PMID:Neurokinetic and myokinetic effects of the peptide xenin on the motility of the small and large intestine of guinea pig. 876 16

The postsynaptic actions of substance P on rat midbrain periaqueductal grey (PAG) neurons were examined using whole-cell patch-clamp recordings in brain slices. Substance P produced an inward current in a subpopulation (60%) of PAG neurons. The substance P induced current was concentration dependent (EC50=27 nM) and was reduced by the NK1, NK2 and NK3 antagonists L-732,138 (20 microM), GR 159897 (3 microM) and SB 218795 (3 microM). The selective NK1, NK2 and NK3 agonists [Sar9,Met(O2)11]-Substance P (100 nM), GR 64349 (300-500 nM) and senktide (300 nM) also produced inward currents in subpopulations of neurons. A greater proportion of substance P-sensitive neurons (70%) than substance P-insensitive neurons (31%) responded to the mu/delta opioid agonist met-enkephalin (10 microM). Substance P reduced the outward current produced by met-enkephalin. The reversal potential of the substance P induced current varied from -5 mV to below -140 mV in the absence of met-enkephalin, and was -105 mV in the presence of met-enkephalin. These results indicate that substance P acts via NK1, NK2 and NK3 receptors to excite subpopulations of opioid-sensitive and insensitive PAG neurons by increasing a non-selective cation conductance and by reducing a K+ current. In addition, substance P has anti-opioid actions that are largely mediated by a reduction in the opioid induced K+ current.
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PMID:Postsynaptic actions of substance P on rat periaqueductal grey neurons in vitro. 1592 8

Evidence implies a role for corticotropin-releasing hormone (CRH) and tachykinins, e.g. substance P (SP) and neurokinin A (NKA) in the pathophysiology of depression. We have previously shown that SP- and NKA-like immunoreactivity (-LI) concentrations were altered in the frontal cortex and striatum of the congenitally 'depressed' Flinders Sensitive Line (FSL) compared to the Flinders Resistant Line (FRL) control rats. It is also known that environmental stress may affect brain levels of tachykinins. In view of these results we decided to superimpose maternal deprivation, an early life environmental stressor, onto the genetically predisposed 'depressed' FSL rats and the FRL control rats and use this paradigm as a model of gene-environment interaction. The adult animals were sacrificed, adrenal glands and brains dissected out and SP-, NKA- and CRH-LI levels were determined in ten discrete brain regions. Maternal deprivation led to a marked increase in SP-LI and NKA-LI levels in the periaqueductal grey (PAG) and entorhinal cortex of the 'depressed' FSL strain while it had no significant effect in the FRL controls. Furthermore, specific strain differences in peptide-LI content were confirmed. No difference was found in relative adrenal gland weight, which is consistent with the finding that CRH-LI levels in the hypothalamus were similar across strains, and insensitive to stress in either strain. Taken together, these data are in line with behavioural experiments showing ameliorating effects of NK1 and NK2 receptor antagonists against anxiety and depression-like symptoms in rodents, and therefore further implicate the tachykinin systems in the pathophysiology of depression and adult life psychopathology.
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PMID:Gene-environment interaction affects substance P and neurokinin A in the entorhinal cortex and periaqueductal grey in a genetic animal model of depression: implications for the pathophysiology of depression. 1747 87