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)

Calmodulin exhibits high-affinity, calcium-dependent binding of 1 mol/mol of the vasoactive intestinal peptide (VIP), secretin, and either the 42- or 43-residue gastric inhibitory peptide (GIP) with dissociation constants of 0.05-0.14 microM. The affinity of VIP for calmodulin approaches its affinity for the cell-surface VIP receptors. These peptides compete with both smooth muscle myosin light chain kinase and glucagon in calmodulin binding. Calculation of amino acid frequencies for eight calmodulin binding peptides (VIP, GIP, secretin, ACTH, beta-endorphin, substance P, glucagon, and dynorphin [Malencik, D. A., & Anderson, S. R. (1982) Biochemistry 21, 3480]) shows a below-average incidence of glutamyl residues, above-average incidence of glutaminyl residues, and average incidence of both aspartyl and asparaginyl residues. Predictions of structure from sequence suggest that the bound peptides contain strongly basic turns and coils in close association with regions having above-average beta-sheet potential. The temperature dependence of glucagon binding by calmodulin shows that the association is enthalpy driven.
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PMID:Binding of hormones and neuropeptides by calmodulin. 618 15

The regional and topographic distribution of endocrine cells in the human intestine was examined by immunohistochemistry. The frequency of endocrine cells was greatest in the small intestine with the rectum next in order. The duodenum and jejunum harbored a large number of different endocrine cell types; the spectrum of cell types gradually narrowed distally in the intestine. 5-Hydroxytryptamine-containing enterochromaffin cells were present in all regions of the intestine and comprised the single largest endocrine cell population. In addition, a minor proportion of these cells contained substance P. The second largest cell population consisted of the glicentin cells, which were notably numerous in the ileum and colon. The somatostatin cells also occurred throughout the digestive tract. Cells storing cholecystokinin, motilin, secretin, or gastric inhibitory polypeptide were more numerous in the proximal and middle small intestine than distally. Gastrin cells were few and occurred in the proximal duodenum only. Other cells in the small intestine reacted with antiserum directed against the common C-terminus of gastrin and cholecystokinin. The number of these cells greatly exceeded the sum of cells reactive to gastrin-specific or cholecystokinin-specific antisera. Cells displaying beta-endorphin, pro-gamma-melanocyte-stimulating hormone, or beta-lipotropin immunoreactivity, or a combination of these, were found in the small intestine. Cells storing neurotensin, glicentin, substance P, or pro-gamma-melanocyte-stimulating hormone increased in number distally in the small intestine. Enterochromaffin cells, glicentin cells, and somatostatin cells were the predominant endocrine cell types in the colon and rectum. The majority of the glicentin-immunoreactive cells also contained glucagon and pancreatic polypeptide-like immunoreactivity. Endocrine cells in the large intestine often possessed basal processes.
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PMID:Endocrine cells in human intestine: an immunocytochemical study. 619 39

The effects of substance P on fluid and amylase secretion were examined in the exocrine pancreas of the rat and the mouse in vivo and in vitro. In the anaesthetised rat, a single intravenous injection of substance P caused an atropine resistant increase in both the basal and caerulein stimulated flow of pancreatic juice and amylase output, but reduced the secretin stimulated pancreatic juice flow. In vitro experiments using superfused mouse pancreatic fragments supported the in vivo result showing that substance P enhanced caerulein stimulated amylase output.
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PMID:Effects of substance P on fluid and amylase secretion in exocrine pancreas of rat and mouse. 620 66

In the present study we examined the abilities of three analogs of substance P, [D-Pro2-, D-Phe7-, D-Trp9]-substance P, [D-Pro2-, D- Trp7 ,9]-substance P and [D-Arg1-, D-Pro2-, D- Trp7 ,9-, Leu11 ]-substance P to alter substance P-induced changes in pancreatic acinar cell function and to occupy substance P receptors. At 30 microM, each analog of substance P lacked agonist activity and inhibited amylase secretion stimulated by substance P receptor agonists. The inhibition was reversible and specific for peptides that interact with substance P receptors (physalaemin, substance P, eledoisin, kassinin ). The analogs of substance P did not inhibit the actions of cholecystokinin, caerulein, gastrin, carbamylcholine, secretin, vasoactive intestinal peptide, PHI, ionophore A23187 or 8Br -cAMP. At high concentrations, [D-Arg1-, D-Pro2-, D- Trp7 ,9-, Leu11 ]-substance P, but not [D-Pro2-, D- Trp7 ,9]-substance P or [D-Pro2-, D-Phe7-, D-Trp9]-substance P, caused a small but significant inhibition of bombesin-stimulated amylase release. For each analog of substance P, the inhibition was competitive in nature in that there was a rightward shift of the dose-response curve for physalaemin-stimulated amylase secretion with no change in efficacy. From Schild plots of the ability of [D-Arg1-, D-Pro2-, D- Trp7 ,9-, Leu11 ]-substance P to inhibit either substance p- or physalaemin-stimulated amylase release, the slopes were not different from unity. For each analog of substance P, there was a close correlation between its ability to inhibit substance P- or physalaemin-stimulated amylase release and its ability to inhibit binding of 125I-labeled substance P or 125I-labeled physalaemin. [D-Arg1-, D-Pro2-, D- Trp7 ,9-, Leu11 ]-substance P was 2-fold more potent than [D-Pro2-, D- Trp7 ,9]-substance P which was 4-fold more potent than [D-Pro2-, D-Phe7-, D-Trp9]-substance P, (i.e., pA2 6.1, 5.9, and 5.2, respectively). For each analog, the dose-response curve for its ability to inhibit physalaemin-stimulated amylase release was superimpossible on the dose-response curve for its ability to inhibit binding of 125I-labeled physalaemin. These results indicate that each of these analogs of substance P is a specific competitive inhibitor of the action of the substance P on dispersed acini from guinea-pig pancreas, and that their abilities to inhibit substance P-induced changes in acinar cell function can be accounted for by their abilities to occupy the substance P receptor.
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PMID:Interaction of substance P antagonists with substance P receptors on dispersed pancreatic acini. 620 26

The colocalization of acetylcholine (ACh) and neuropeptides (e.g., substance P and enkephalins) in the splanchnic nerve terminals suggests that these compounds might interact to modulate adrenal catecholamine release. Use has been made of primary monolayer and suspension cultures of bovine adrenal chromaffin cells to investigate postsynaptic receptor interactions between acetylcholine and a number of neuropeptides endogenous to the adrenal medulla and splanchnic nerve. The cells have both nicotinic and muscarinic acetylcholine receptors, but only the nicotinic receptors stimulate catecholamine release. Substance P, somatostatin, and the enkephalins all produced an inhibition of the ACh-evoked secretion of catecholamines, but their potency ranged over 100-fold. Substance P was the most potent with a mean inhibitory concentration (IC50) of 10(-6) M and Leu-enkephalin the least potent with an IC50 greater than 10(-4) M. These pharmacological effects were monitored conveniently by measuring the release of [3H]norepinephrine preloaded into the cells or alternatively, "on-line" by measuring ATP released into an incubation medium containing luciferin and firefly tail extract (luciferase). Of interest, the endogenous enkephalin heptapeptide (Met-enkephalin Arg6-Phe7) and "big" Met-enkephalin (BAM- 22P ) were some 100-fold more effective than Leu- or Met-enkephalin at inhibiting the nicotinic secretin of catecholamines, suggesting that a unique opiate receptor may be involved. Substance P had two distinct actions on the nicotinic response: (1) substance P inhibited acetylcholine-induced release of catecholamines; and (2) substance P protected against acetylcholine-induced desensitization of catecholamine release. With regard to (1), substance P inhibited the secretion of catecholamines and ATP evoked by acetylcholine or nicotine but not that evoked by K+ or veratridine, nor did substance P by itself affect secretion. Substance P appeared to interact with a regulatory site on the acetylcholine receptor - ionophore complex. Substance P receptors on chromaffin cells have similar structural requirements for activation as do substance P receptors in other substance P responsive tissues. With regard to (2), substance P (greater than 5 X 10(-6) M) completely protected against desensitization of catecholamine release produced by acetylcholine (greater than 10(-4) M) or nicotine (greater than 2.5 X 10(-6) M) with no effect on K+-induced desensitization.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Receptors and receptor modulation in cultured chromaffin cells. 620 33

Binding of 125I-labeled vasoactive intestinal peptide (VIP) to dispersed enterocytes prepared from guinea pig small intestine was saturable, temperature dependent, and reversible, and reflected interaction of the labeled peptide with a single class of binding sites. Each enterocyte possessed approximately 60,000 binding sites and binding of the tracer to these sites could be inhibited by VIP [concentration for half-maximal effect (Kd), 12 nM] and by secretin (Kd greater than 1 micro M), but not by glucagon, gastrin, cholecystokinin, calcitonin, bombesin, litorin, physalaemin, substance P, eledoisin, serotonin, carbamylcholine, or histamine. With VIP and secretin, there was a close correlation between the relative potency for inhibition of binding of 125I-VIP and that for increasing cellular cAMP. For a given peptide, however, a 10-fold higher concentration was required for half-maximal inhibition of binding than for half-maximal stimulation of cellular cAMP. In addition to inhibiting binding of 125I-VIP and increasing cellular cAMP in enterocytes, secretin caused an increase in short-circuit current across guinea pig small intestine in vitro. Prostaglandin E1 increased cellular cAMP, but did not alter binding of 125I-VIP and the increase in cAMP caused by prostaglandin E1 plus VIP or secretin was equal to the sum of the increase caused by each agent alone.
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PMID:Receptors for vasoactive intestinal peptide and secretin on small intestinal epithelial cells. 624 88

We have prepared (125)I-labeled cholecystokinin and have examined the kinetics, stoichiometry, and chemical specificity with which the labeled peptide binds to dispersed acini from guinea pig pancreas. Binding of (125)I-labeled cholecystokinin was reversible, temperature-dependent, saturable, specific, and localized to the plasma membrane. Each acinar cell possessed approximately 9000 binding sites, and binding of the labeled peptide to these sites could be inhibited by cholecystokinin and structurally related peptides (e.g., gastrin and caerulein) as well as by nonpeptide competitive antagonists of the action of cholecystokinin. Binding was not inhibited by other pancreatic secretagogues such as secretin, vasoactive intestinal peptide, glucagon, physalaemin, eledoisin, kassinin, substance P, carbamoylcholine, litorin, or ranatensin or by bovine pancreatic polypeptide, atropine, neurotensin, leucineenkephalin, methionine-enkephalin, or cyclic somatostatin. With agonists as well as antagonists there was a good correlation between occupation of cholecystokinin binding sites and changes in acinar cell function. With each of six different peptide agonists maximal stimulation of enzyme secretion occurred with 40% receptor occupation and occupation of the remaining 60% caused a progressive decrease in stimulated amylase release. Agonists, but not antagonists, accelerated the dissociation of bound (125)I-labeled cholecystokinin, and these findings suggest that, in pancreatic acini, radiolabeled cholecystokinin binds to at least one class of interacting binding sites whose affinities are influenced by the extent to which these sites are occupied by agonists but not the extent to which they are occupied by antagonists.
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PMID:Interaction of cholecystokinin with specific membrane receptors on pancreatic acinar cells. 624 21

Polypeptide-hormone producing cells were localized in the alimentary tract and cerebral ganglion of Ciona intestinalis using cytochemical, immunocytochemical and electron-microscopical methods. Antisera to the following peptides of vertebrate type were employed: bombesin, human prolactin (hPRL), bovine pancreatic polypeptide (PP), porcine secretin, motilin, vasoactive intestinal polypeptide (VIP), beta-endorphin, leu-enkephalin, met-enkephalin, neurotensin, 5-hydroxytryptamin (5-HT), cholecystokinin (CCK), human growth (GH), ACTH, corticotropin-like intermediate lobe peptide (CLIP) and gastric inhibitory peptide (GIP). Immunoreactive cells were found both in the alimentary tract epithelium and in the cerebral ganglion for bombesin, PP, substance P, somatostatin, secretin and neurotensin. Additionally, in the cerebral ganglion only, there were cells immunoreactive for beta-endorphin, VIP, motilin and human prolactin. 5-HT positive cells, however, were restricted to the alimentary tract. No immunoreactivity was obtained either in the cerebral ganglion or in the alimentary tract with antibodies to leu-enkephalin, met-enkephalin, CCK, growth hormone, ACTH, CLIP and GIP. Prolactin-immunoreactive and pancreatic polypeptide-immunoreactive cells were argyrophilic with the Grimelius' stain and were found in neighbouring positions in the cerebral ganglion. At the ultrastructural level five differently granulated cell types were distinguished in the cerebral ganglion. Granules were present in the perikarya as well as in axons. The possible functions of the peptides as neurohormones, neuroregulators and neuromodulators are discussed.
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PMID:Gastro-intestinal and neurohormonal peptides in the alimentary tract and cerebral complex of Ciona intestinalis (Ascidiaceae). 627 5

We prepared 125I-secretin and studied the kinetics, stoichiometry, and chemical specificity with which the labeled peptide binds to dispersed acini prepared from guinea pig pancreas. Iodinated secretin retained intrinsic biological activity in that it was as effective but 2.5-times less potent than native secretin in its ability to bind to pancreatic acini and to increase cellular cAMP. Scatchard analysis of binding of 125I-secretin indicated that each pancreatic acinar cell has approximately 93,000 binding sites, half of which are occupied by 11 nM iodinated secretin. Binding of 125I-secretin was rapid, reversible, saturable, specific, and temperature dependent. Binding of 125I-secretin was inhibited by secretin, vasoactive intestinal peptide, PHI, and Gila monster venom but not by glucagon, gastric inhibitory polypeptide, cholecystokinin, caerulein, gastrin, bovine pancreatic polypeptide, somatostatin, neurotensin, leucine-enkephalin, methionine-enkephalin, carbachol, bombesin, litorin, eledoisin, physalaemin, or substance P. With agonists (secretin, vasoactive intestinal peptide, PHI, or Gila monster venom), as well as antagonists (C-terminal fragments of secretin), there was a close correlation between their relative potencies for inhibiting binding of 125I-secretin and their relative potencies for increasing cAMP (agonists) or inhibiting the secretin-induced increase in cAMP (antagonists). For a given agonist, however, a 40-fold higher concentration was required for half-maximal inhibition of binding of 125I-secretin than was required to produce a half-maximal increase in cellular cAMP. Thus, maximal stimulation of cellular cAMP occurs when approximately one-third of the secretin receptors are occupied by an agonist.
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PMID:Use of 125I-secretin to identify and characterize high-affinity secretin receptors on pancreatic acini. 630 17

Vasoactive intestinal peptide (VIP) has been shown to increase cyclic AMP content in isolated epithelial cells of rat ventral prostate. The stimulatory effect of VIP was dependent on time and temperature and was potentiated by a phosphodiesterase inhibitor. At 15 degrees C, the response occurred in the 1 X 10(-10)-10(-7)M range of VIP concentrations. Half-maximal stimulation of cellular cyclic AMP was obtained at 1.4 nM and maximal stimulation (3-fold basal level) at about 100 nM VIP. Chicken VIP and porcine secretin were agonists of porcine VIP but exhibited a 2-times higher and a 170-times lower potency, respectively. A high concentration (1 X 10(-6)M) of glucagon, somatostatin, neurotensin, substance P, Met-enkephalin or Leu-enkephalin did not modify cAMP levels. The finding of a VIP-stimulated cAMP system in rat prostatic epithelial cells together with the previous characterization of high-affinity receptors for VIP in the same cell preparation, as well as the presence of VIP-containing neurones innervating the male genitourinary tract, strongly suggest that VIP may be involved in prostatic growth regulation and function.
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PMID:Cyclic AMP-stimulating effect of vasoactive intestinal peptide in isolated epithelial cells of rat ventral prostate. 631 52


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