Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

First incubating guinea pig pancreatic acini with carbachol reduced the subsequent stimulation of amylase release caused by carbachol, cholecystokinin octapeptide (CCK-8), and bombesin but not that caused by vasoactive intestinal peptide, substance P, 8-bromoadenosine 3',5'-cyclic monophosphate, A23187, or 12-O-tetradecanoylphorbol-13-acetate. Carbachol also reduced the subsequent binding of N-[3H]methylscopolamine, 125I-CCK-8, and 125I-[Tyr4]bombesin. Pancreatic acini possess a high-affinity class of cholinergic receptors and a low-affinity cholinergic receptors appears to produce the reduction in carbachol-stimulated amylase release and binding of N-[3H]methylscopolamine. First incubating acini with carbachol caused a complete loss of high-affinity cholinergic receptors with no change in the number or affinity of low-affinity cholinergic receptors. Carbachol occupation of low-affinity cholinergic receptors appears to produce the reduction in CCK-8- and bombesin-stimulated amylase release and in binding of 125I-CCK-8 and 125I-[Tyr4]bombesin. Acini possess two classes of CCK receptors. One class has a high affinity for CCK-8; the other class has a low affinity for CCK-8. First incubating acini with carbachol caused a 60% decrease in the number of high-affinity CCK receptors with no change in the number of low-affinity receptors or the affinities of either class of receptors for CCK-8. Acini possess a single class of bombesin receptors, and first incubating acini with carbachol caused a 40% decrease in the number of bombesin receptors with no change in their affinity for bombesin. 12-O-tetradecanoyl phorbol-13-acetate reproduced the action of carbachol on binding of N-[3H]methylscopolamine and 125I-CCK-8 but not on binding of 125I-[Tyr4]bombesin, suggesting that carbachol activation of protein kinase C may in some way mediate the effect of carbachol on receptors for carbachol and those for CCK but not that on receptors for bombesin.
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PMID:Carbachol desensitizes pancreatic enzyme secretion by downregulation of receptors. 168 17

Animal studies suggest that the neuropeptides, substance P and vasoactive intestinal peptide (VIP), may influence carotid body chemoreceptor activity and that substance P may take part in the carotid body response to hypoxia. The effects of these peptides on resting ventilation and on ventilatory responses to hypoxia and to hypercapnia have been investigated in six normal humans. Infusions of substance P (1 pmol.kg-1.min-1) and of VIP (6 pmol.kg-1.min-1) were compared with placebo and with nitroprusside (5 micrograms.kg-1.min-1) as a control for the hypotensive action of the peptides. Both peptides caused significantly less hypotension than nitroprusside. Substance P and nitroprusside caused significantly greater increases in ventilation and in the hypoxic ventilatory response than VIP. No changes were seen in hypercapnic sensitivity. The stimulation of ventilation and the differential effects on ventilatory chemosensitivity that accompanied hypotension are consistent either with stimulation of carotid body chemoreceptor activity or with an interaction with peripheral chemoreceptor input to the respiratory center, as is seen in animals. The similar cardiovascular but different ventilatory effects of the peptides suggest that substance P may also stimulate the carotid body in a manner independent of the effect of hypotension. This is consistent with a role of substance P in the hypoxic ventilatory response in humans.
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PMID:Ventilatory effects of substance P, vasoactive intestinal peptide, and nitroprusside in humans. 169 Feb 2

1. Arteriolar diameter was measured using an optical method in preparations of guinea-pig submucosal plexus in vitro. Electrical stimulation of one or more neurones in ganglia of the submucosal plexus causes a cholinergic vasodilatation in normal animals. The vasomotor innervation to the arterioles was studied in guinea-pigs in which the extrinsic nerves to the intestine had been removed. Tissues were processed for immunohistochemistry after the in vitro experiments. 2. Extrinsic denervation resulted in complete loss of catecholamine fluorescence, NPY (neuropeptide Y) and CGRP (calcitonin gene-related peptide) immunofluorescence around the blood vessels and no neurogenic vasoconstriction was observed up to 60 days post-denervation. Vasodilatation in response to ganglionic stimulation was increased; smaller arterioles (outside diameter less than 40 microns) showed a greater enhancement of neurogenic vasodilatation than larger arterioles. 3. Nerve-evoked vasodilatations were only partially inhibited by muscarinic antagonists at 30-60 days after extrinsic denervations. 4. The non-cholinergic neurogenic vasodilatation was abolished by the substance P antagonists, spantide, [D-Arg1, D-Pro2, D-Trp7.9, Leu11]substance P and [D-Arg1, D-Phe5, D-Trp7.9, Leu11]substance P. These antagonists did not alter the cholinergic vasodilatation in normal or extrinsically denervated arterioles. 5. Exogenous substance P dilated all submucosal arterioles; the concentration which produced half-maximal vasodilatations was 2.5 mM in both normal and extrinsically denervated arterioles. Substance P antagonists inhibited the vasodilatation caused by substance P at concentrations similar to those needed to block nerve-mediated vasodilatation. 6. There was a strong correlation between the finding of non-cholinergic vasodilatation in response to ganglionic stimulation, and the presence of substance P-immunoreactive fibres running from ganglion to arteriole. This correlation did not exist for VIP (vasoactive intestinal peptide). 7. These results suggest that intrinsic intestinal substance P-containing nerve fibres supply submucosal arterioles after sympathetic efferents and sensory afferents are removed. Stimulation of these nerves releases substance P to produce arteriolar dilatation.
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PMID:Substance P mediates neurogenic vasodilatation in extrinsically denervated guinea-pig submucosal arterioles. 169 Dec 91

Endothelin-1 is a 21 amino acid peptide originally isolated from porcine aortic endothelium and has recently been localized within the central nervous system. We have administered endothelin-1 in a dynamic perfusion system in order to study its possible effects on the rat hypothalamus and anterior pituitary. Tissue (hypothalami or quartered pituitaries) was placed into plastic chambers and was perfused with oxygenated Krebs-bicarbonate solution. After an interval to establish stable basal peptide release, endothelin-1 was administered at two doses (0.1 and 1 microM) and the release of substance P, vasoactive intestinal peptide, 7B2, and somatostatin was measured, the last being detectable only in hypothalamic perfusates. Both concentrations of endothelin-1 led to a significant increase (P less than 0.01) in the release of substance P from the hypothalamus and pituitary, but not of vasoactive intestinal peptide, 7B2, or somatostatin. Thus after the 0.1 microM and 1 microM endothelin-1 perfusion substance P release from the hypothalamus increased by 125 +/- 5% and 215 +/- 15% (mean +/- SEM) of basal and from the pituitary by 168 +/- 8% and 276 +/- 15% (mean +/- SEM). No change occurred in the output of ACTH or other pituitary hormones. The release of substance P from hypothalamus or pituitary after stimulation with endothelin-1 was not blocked when a calcium free medium was used. Endothelin-1 binding sites were identified on rat pituitary cell membranes. These findings suggest the possibility that endothelin may act as a paracrine substance, neurotransmitter, or neuromodulator in the hypothalamo-pituitary axis.
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PMID:Release of substance P from rat hypothalamus and pituitary by endothelin. 169 95

Several lines of evidence suggest a possible role for mast cell proteases in modulating the biologic effects of neuropeptides. To explore the potential of such interactions in human airway, we examined the activity of human tryptase, the major secretory protease of human lung mast cells, against several neuropeptides with proposed regulatory functions in human airway. Using highly purified tryptase obtained from extracts of human lung, we determined the sites and rats of hydrolysis of vasoactive intestinal peptide (VIP), peptide histidine-methionine (PHM), calcitonin gene-related peptide (CGRP), and the tachykinins substance P (SP), neurokinin A (NKA), and neurokinin B (NKB). Tryptase hydrolyzes VIP rapidly at several sites (Arg12, Arg14, Lys20, and Lys21) with an overall kcat/Km of 1.5 x 10(5) M-1 s-1 and hydrolyzes PHM primarily at a single site (Lys20) with a kcat/Km of 1.9 x 10(4) M-1 s-1. Tryptase also rapidly hydrolyzes CGRP at two sites (Arg18 and Lys24) with a kcat/Km of 2.7 x 10(5) M-1 s-1. The tachykinins are not hydrolyzed by tryptase. These observations raise the possibility that tryptase-mediated degradation of the bronchodilators VIP and PHM combined with exaggerated mast cell release of tryptase may contribute to the increase in bronchial responsiveness and the decrease in immunoreactive VIP in airway nerves associated with asthma. The favorable rates of hydrolysis of CGRP suggest that tryptase may also terminate the effects of CGRP on bronchial and vascular smooth muscle tone and permeability.
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PMID:Degradation of airway neuropeptides by human lung tryptase. 169 72

Antisera raised against neuron specific enolase (NSE), substance P, vasoactive intestinal peptide (VIP) and tyrosine hydroxylase (TH) were used to reveal nerve fibres in the wall of the canine small and large intestine. The circular muscle of the colon was innervated by nerve fibre bundles that ran parallel to the muscle throughout its thickness. A plexus of fibre bundles was found against the inner (submucosal) surface of the circular muscle. Fibres with substance P, VIP and TH immunoreactivity all contributed to this innervation. The circular muscle of the small intestine was distinctly separated into outer and inner layers by a dense plexus of nerve fibres, the deep muscular plexus. The outer and inner circular muscle were innervated by substance P, VIP and TH fibres. Extrinsic denervation through the severing of nerve fibres in the mesentery caused TH fibres in the intestine to degenerate, but had no detectable effect on the fibres with substance P or VIP immunoreactivity. Myectomy (the removal of the myenteric plexus from the full circumference of the intestine over a distance of 2-3 cm), performed 7-13 days before tissue was taken, resulted in an almost complete loss of substance P fibres from the circular muscle of the colon and the outer circular muscle of the small intestine. However, many fibres persisted in the deep muscular plexus of the small intestine, and most fibres remained in its inner circular muscle. The changes in distribution of VIP fibres were almost identical, except that a small proportion of reactive fibres remained in the circular muscle of the colon and the outer circular muscle of the small intestine. It is concluded that the circular muscle layers of the small intestine and colon have dual sources of intrinsic nerve supply: the myenteric ganglia supply fibres primarily to the outer part of the muscle and the submucous ganglia supply fibres to the inner muscle. The present study further demonstrated that VIP fibres ran anally in the myenteric plexus of both the small and large intestine, whereas substance P fibres ran orally in the large intestine and both orally and anally in the small intestine. The innervation of the muscularis mucosae and mucosa by substance P and VIP fibres was not affected by myectomy or extrinsic denervation, and these structures are therefore likely to be innervated by nerve cells in the submucous ganglia.
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PMID:Projections of substance P, vasoactive intestinal peptide and tyrosine hydroxylase immunoreactive nerve fibres in the canine intestine, with special reference to the innervation of the circular muscle. 169 12

Two novel neuromedin C analogs [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C and [Leu9-psi-CH2NH-Leu10]neuromedin C, were synthesized by rapid solid phase methods and examined for their abilities to inhibit neuromedin C-stimulated amylase release by isolated rat pancreatic acini. Both analogs significantly inhibited maximally stimulated amylase release by neuromedin C in a dose-dependent manner with maximal inhibition seen at concentrations of 100 and 300 microM of [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C and [Leu9-psi-CH2NH-Leu10]neuromedin C, respectively. The IC50 (concentration required to half-maximally inhibit neuromedin C-stimulated amylase release) was 1.5 microM for [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C compared to a 13.4 microM IC50 for [Leu9-psi-CH2NH-Leu10]neuromedin C. The [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C analog produced a parallel rightward shift in the neuromedin C dose-response curve and Schild plots of the inhibition data gave a slope of 0.969 +/- 0.121 and a pA2 (apparent affinity for the acinar cell receptor in terms of neuromedin C receptor-stimulated amylase release) of 100 nM. While [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C significantly inhibited both neuromedin B- and gastrin releasing peptide-stimulated amylase release, the analog did not inhibit amylase release in response to either cholecystokinin octapeptide, vasoactive intestinal peptide, substance P, carbamylcholine, the Ca2+ ionophore A23187, forskolin, or 8-bromo-cyclic AMP. The results demonstrate that [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C is a potent, specific, and competitive antagonist for neuromedin C and peptides of the gastrin releasing peptide family and may serve as a useful molecule for exploring the physiological role of these peptides.
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PMID:[D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C antagonizes neuromedin C-stimulated amylase release by acini isolated from the rat pancreas. 169 79

In the extrinsically denervated smooth muscle esophagus of the hen anesthetized with urethane (1 g/kg, i. m.), it was studied whether peptidergic neurons in the intramural plexus are involved in the intrinsic reflex. Ascending and descending contractions, and descending relaxation were induced by electrical stimulation of a narrow segment of the esophagus. Naloxone (1 microM), desensitization to substance P (0.3 microM) and spantide (20 microM) inhibited the ascending and descending contractions, respectively. The degree of the inhibition of the contractile response by a combination of naloxone and substance P was nearly the same as that by a single administration of naloxone or substance P. The ascending and descending contractions were reduced to one-third of the control by hexamethonium (100 microM) and abolished by atropine (10 microM). The descending relaxation was abolished after desensitization to vasoactive intestinal peptide (0.3 microM). Taken together the results suggest that in the hen's esophagus, opioid- and substance P-containing neurons in the intramural plexus may act as preganglionic neurons of cholinergic motor neurons in the ascending and descending excitatory pathways and that vasoactive intestinal peptide-containing neurons are involved in the descending inhibitory pathway.
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PMID:Intrinsic reflexes mediated via peptidergic neurons in the smooth muscle esophagus of the hen. 169 22

The neuropeptides substance P, neuropeptide Y, neurotensin, and vasoactive intestinal peptide are present in normal rat anterior pituitary gland and hypothalamus and can influence the secretion of classical pituitary hormones. We investigated the effects of estrogen manipulation on pituitary and hypothalamic expression of these four peptides by specific RIAs and cDNA probe analysis. Surgical ovariectomy produced a significant rise in the pituitary content of substance P immunoreactivity (IR) (130.2 +/- 4.8 fmol/gland vs. control 29.1 +/- 2.2, P less than 0.001), neuropeptide Y IR (34.9 +/- 3.9 vs. 19.6 +/- 2.0, P less than 0.05) and neurotensin IR (85.1 +/- 8.2 vs. 62.4 +/- 7.2, P less than 0.05), while vasoactive intestinal peptide IR showed a fall (201.2 +/- 18.8 vs. 285.4 +/- 25.9, P less than 0.05). These patterns were reversed with estrogen replacement or high dose estrogen treatment. Changes in peptide content were accompanied by parallel changes in the mRNA for each peptide. Treatment with an antiestrogen (tamoxifen) resulted in no change in substance P, neuropeptide Y, and neurotensin expression, while vasoactive intestinal peptide IR content decreased to below the assay detection limit. Hypothalamic expression of these peptides did not change with any of the treatments. These results indicate that: 1) the control of the pituitary expression of the four peptides under the influence of estrogen occurs predominantly at the level of gene transcription and 2) normalization of the castration induced changes by exogenous estrogen replacement suggests the changes to be mediated by the absence of this steroid. The regulation of the pituitary expression of these peptides by estrogen support the possibility of their having an autocrine or paracrine role.
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PMID:The regulation of neuropeptide expression in rat anterior pituitary following chronic manipulation of estrogen status: a comparison between substance P, neuropeptide Y, neurotensin, and vasoactive intestinal peptide. 169 87

Using immunocytochemistry, the authors studied the peptidergic innervation to the vasculature of the optic nerve and retina in the rhesus monkey and rat. In the monkey, beaded nerve fibers immunoreactive to the vasoactive peptides, calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), substance P (SP), and vasoactive intestinal peptide (VIP), are present in the adventitia and perivascular space along the course of the central retinal artery within the optic nerve. The CGRP and SP immunoreactivities fully co-localize. Perivascular peptidergic nerve fibers terminate as the blood vessel enters the globe and do not follow the branches of the central retinal artery inside the eye. Within the substance of the optic nerve behind the lamina cribrosa, small blood vessels occasionally are supplied with CGRP-, SP-, and sometimes NPY- or VIP-immunoreactive nerve fibers. Of special note, fine nerve fibers not clearly related to blood vessels are seen within the lamina cribrosa; their simultaneous immunoreactivity to CGRP and SP suggests a sensory function. In the rat as in the monkey, the retinal arterioles beyond the surface of the optic disc lack evident peptidergic innervation. Perhaps an explanation for the known physiologic reactivity of the retinal circulation to neurohumors in the absence of recognizable peripheral innervation can be based on comparison to the brain where intraparenchymal blood vessels may be regulated by local neurons. Since the inner plexiform layer has abundant amacrine-derived nerve processes containing classical neurotransmitters and/or neuropeptides, a local mechanism coupled to intrinsic retinal activity might contribute to the regulation of the circulation.
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PMID:Peptidergic innervation of the retinal vasculature and optic nerve head. 169 44


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