Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Partially purified nerve varicosities prepared from canine small intestinal myenteric, deep muscular and submucosal plexuses were found to contain, by radioimmunoassay, gastrin-releasing polypeptide (GRP), substance P, Leu-enkephalin, Met-enkephalin, vasoactive intestinal polypeptide (VIP) and neurokinin A, but did not contain detectable amounts of neurokinin B. In all three plexus preparations, VIP was present in the highest concentration. In contrast to other species, GRP and the enkephalins were found to be present in relatively high concentrations in the submucosal plexus and GRP was present in low concentrations in the deep muscular plexus. Equal concentrations of substance P and neurokinin A were found in the myenteric and deep muscular plexus preparations but greater concentrations of substance P relative to neurokinin A were found in the submucosal plexus preparations. On reverse phase HPLC, a major peak of immunoreactivity occurred at the retention times of standard preparations for all six neuropeptides measured. Significant heterogeneity was found for GRP- and VIP-like immunoreactivity, especially in the submucosal plexus preparations. These partially purified canine small intestine nerve varicosity preparations may prove of value in studying release mechanisms for, and the posttranslational processing of, neuropeptides.
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PMID:Canine myenteric, deep muscular, and submucosal plexus preparations of purified nerve varicosities: content and chromatographic forms of certain neuropeptides. 234 94

Partially purified nerve varicosities (PV) prepared from guinea pig ileal myenteric plexus were found to contain, by radioimmunoassay, gastrin-releasing polypeptide (GRP), substance P (SP), galanin, Leu-enkephalin (LE), Met-enkephalin (ME), and vasoactive intestinal polypeptide (VIP). SP was present in the highest concentration followed by, in descending order, ME, LE, VIP, GRP and galanin. On reverse-phase HPLC, SP-, LE- and ME-like immunoreactivity in the PV preparation eluted at retention times similar to their synthetic analogues, galanin-like immunoreactivity eluted at a retention time different from that of synthetic porcine galanin and VIP-like immunoreactivity eluted at the retention time of synthetic guinea pig VIP. GRP-like immunoreactivity, on reverse-phase HPLC, eluted at retention times close to that of synthetic porcine GRP-(1-27) and its major oxidized form. Evidence was obtained for the presence of an alpha-neurokinin-like immunoreactive entity and an unidentified SP-like immunoreactive entity in guinea pig myenteric plexus.
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PMID:Characterization of content and chromatographic forms of neuropeptides in purified nerve varicosities prepared from guinea pig myenteric plexus. 245 23

Smooth muscle cells were isolated from the fundus of the canine gallbladder and examined for the presence of opioid receptors. The cells contracted in a concentration-dependent manner in response to three opioid peptides (Met-enkephalin, dynorphin1-13 and Leu-enkephalin), which are known derivatives of opioid precursors present in myenteric neurons of the gut. The order of potency was Met-enkephalin greater than dynorphin1-13 greater than Leu-enkephalin. The contractile response to opioid agonists was selectively inhibited by opioid antagonists (naloxone and Mr2266) but not by muscarinic, CCK/gastrin or tachykinin antagonists. Equivalent responses to the three opioid peptides exhibited differential sensitivity to preferential antagonists of mu (naloxone) and kappa (Mr2266) opioid receptors consistent with the presence of the three main types of opioid receptors (mu, delta and kappa) on canine gallbladder muscle cells.
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PMID:Characterization of opioid receptors on isolated canine gallbladder smooth muscle cells. 289 8

A dipeptidyl carboxypeptidase, which cleaved the Gly3-Phe4 bond of enkephalins, was purified from guinea pig serum 420-fold. The optimum pH of the enzyme was in the neutral range (pH 7.25), and the molecular weight was estimated to be approx. 280,000. The enzyme hydrolyzed Met- and Leu-enkephalin with Km values of 0.30 and 0.50 mM, respectively. The enzyme was inhibited by metal chelators and p-chloro-mercuribenzoate. Captopril showed high inhibitory potency, while phosphoramidon and Phe-Ala showed no effect on the enzyme activity. Therefore, the obtained enzyme can be classified as an angiotensin-converting enzyme (EC 3.4.15.1). Among the bioactive peptides examined, bradykinin and angiotensin I were hydrolyzed by the enzyme. Angiotensin III showed a stronger inhibitory effect than that of angiotensin II. Substance P, gastrin I, and secretin were also inhibitory toward the enzyme activity. On high-performance liquid chromatography analysis, Met-enkephalin-Arg6-Phe7 and Leu-enkephalin-Arg6 were cleaved sequentially at the second peptide bond of the C terminus. Thus, the dipeptidyl carboxypeptidase in guinea pig serum may play a role not only in the angiotensin-bradykinin system but also in the metabolism of circulating enkephalins and other bioactive peptides.
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PMID:Enkephalin-degrading dipeptidyl carboxypeptidase in guinea pig serum: its properties and action on bioactive peptides. 299 Mar 46

Ventral thoracic neurosecretory cells (VTNCs) of the blowflies, Calliphora erythrocephala and C. vomitoria, innervating thoracic neuropil and the dorsal neural sheath of the thoracico-abdominal ganglion have been shown to be immunoreactive to a variety of mammalian peptide antisera. In the neural sheath the VTNC terminals form an extensive neurohaemal network that is especially dense over the abdominal ganglia. The same areas are invaded by separate, but overlapping serotonin-immunoreactive (5-HT-IR) projections derived from neuronal cell bodies in the suboesophageal ganglion. Immunocytochemical studies with different antisera, applied to adjacent sections at the light-microscopic level, combined with extensive cross-absorption tests, suggest that the perikarya of the VTNCs contain co-localized peptides related to gastrin/cholecystokinin (CCK), bovine pancreatic polypeptide (PP), Met- and Leu-enkephalin and Met-enk-Arg6-Phe7 (Met-enk-RF). Electron-microscopic immunogold-labeling shows that some of the terminals in the dorsal sheath react with several of the individual peptide antisera, whilst others with similar cytology are non-immunoreactive. In the same region, separate terminals with different cytological characteristics contain 5-HT-IR. Both 5-HT-IR and peptidergic terminals are localized outside the cellular perineurium beneath the acellular permeable sheath adjacent to the haemocoel. Hence, we propose that various bioactive substances may be released from thoracic neurosecretory neurons into the circulating haemolymph to act on peripheral targets. The same neurons may also interact by synaptic or modulatory action in the CNS in different neuropil regions of the thoracic ganglion.
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PMID:Light- and electron-microscopic immunocytochemistry of peptidergic neurons innervating thoracico-abdominal neurohaemal areas in the blowfly. 318 Jan 85

The distribution of enkephalin-like immunoreactive material has been studied in the CNS of C. vomitoria. The presence of both Met- and Leu-enkephalin-related peptides is suggested by differential immunostaining with a variety of antisera. Comparisons made between certain of the enkephalin-immunoreactive perikarya, nerve fibres and terminals with cells in corresponding positions as evidenced in previously published neuroanatomical studies of the dipteran brain have suggested specific enkephalinergic pathways. As examples, one Met-enkephalin-immunoreactive neuron appears to link the lobula with the dorsal protocerebrum, and a group of Leu-enkephalin cells in the pars intercerebralis appear to have arborisations in both the central body (fan-shaped body) and the tritocerebral neuropil around the oesophageal foramen. Neuronal pathways of this type indicate that the enkephalin-like peptides of the fly brain are functioning as neurotransmitters and/or neuromodulators. In the thoracic ganglia, symmetrically arranged cells, immunoreactive to both Met- and Leu-enkephalin antisera, are positioned ventrally in pairs on either side of the mid-line in a sagittal plane. Very little immunoreactive material is observed in the neuropil, however, and the source of the accumulation of Leu-enkephalin-immunoreactivity in the dorsal neural sheath is not certain. It is suggested that this material, in contrast to that present in areas of the brain, acts as a neurohormone and that it may have a physiological role following its release into the haemolymph. The enkephalin-like immunoreactive material of certain neurons identified within the brain and thoracic ganglion shows a complex pattern of co-existence with pancreatic polypeptide- and gastrin/cholecystokinin-like peptides.
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PMID:Mapping of enkephalin-related peptides in the nervous system of the blowfly, Calliphora vomitoria, and their co-localization with cholecystokinin (CCK)- and pancreatic polypeptide (PP)-like peptides. 334 52

Carcinoid tumors of the middle ear are rare, with only three previously reported cases. The authors report the light and electron microscopic and immunohistochemical features of two carcinoid tumors that occurred in a 34-year-old female and a 21-year-old male. Both presented with unilateral hearing loss. By light microscopic examination, both were characterized by trabecula of tall columnar cells with basal nuclei and no mitotic activity. Electron microscopic examination demonstrated large numbers of pleomorphic neurosecretory granules, perinuclear aggregates of intermediate filaments, cell junctions, and surface microvillous processes. Some cells contained intermediate filaments forming tonofilaments and lacked secretory granules. These cells stained for cytokeratin by immunoperoxidase and separated the neuroendocrine cells from the underlying basal lamina. The cells in this tumor stained for the molluscan cardioexcitatory peptide. Cells in both tumors also stained for pancreatic polypeptide. Neither case stained for lysozyme, insulin, glucagon, somatastatin, gastrin, substance P, thyroid-stimulating hormone, adrenocorticotropic hormone, Met-enkephalin, Leu-enkephalin, neuropeptide Y, peptide YY, neurotensin, Bombesin, serotonin, neuron-specific enolose, glial and neural filaments, S-100 protein, cholecystokinin, beta-endorphin, beta-human chorionic gonadotropin, luteinizing hormone/follicle-stimulating hormone, vasoactive intestinal polypeptide, prolactin or calcitonin. Carcinoid tumor of the middle ear can be distinguished from paraganglioma and middle ear adenoma.
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PMID:Carcinoid tumors of the middle ear. 357 33

Previous studies have demonstrated mostly inhibitory effects of elevated plasma glucose levels on gastric exo- and endocrine as well as motor functions. Because increased plasma glucose levels reduce vagal activity via the central nervous system, it remains unclear if glucose exerts a direct effect on gastric functions. Therefore, our study was designed to determine the effect of acute changes in glucose concentrations on the release of gastrin and bombesin-like immunoreactivity (BLI) from the isolated perfused rat stomach. Acute elevations of perfusate glucose from 100 to 200 mg/dl or from 100 to 300 mg/dl augmented BLI secretion significantly without affecting gastrin release. During an acute decrease from 200 to 30 mg/dl, the secretion of both peptides remained unchanged. When acetylcholine was administered to stimulate BLI and gastrin secretion, the elevation of perfusate glucose to 200 mg/dl and the decrease to 30 mg/dl attenuated BLI secretion, whereas gastrin secretion remained unchanged compared with the control experiments at 100 mg/dl glucose. On the other hand, the perfusion of vasoactive intestinal peptide (VIP) and Leu-enkephalin had no effect on BLI and gastrin secretion during 100 mg/dl glucose perfusion, but both peptides elicited a significant stimulatory effect on BLI secretion during a perfusate glucose concentration of 200 mg/dl without affecting gastrin secretion. In conclusion, our study demonstrates first that an acute increase of glucose augments basal BLI secretion. Second, cholinergically induced BLI secretion is attenuated by hypo- and hyperglycemia. Third, hyperglycemia augments BLI secretion in response to the neuropeptides VIP and Leu-enkephalin. Fourth, basal and stimulated gastrin secretion remains unchanged during acute alterations of perfusate glucose levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulatory glucose effect on bombesin-like immunoreactivity and gastrin secretion from isolated perfused rat stomach. 372 Oct 63

A study was made of the effect of the low-molecular neuropeptides, leu- and met-enkephalins, thyroliberin (TRH), the C-end tripeptides, gastrin (MAF) and oxytocin (MIF) on the content of biogenic monoamines and their metabolites and on the production of humoral antibodies to sheep red blood cells. The action of the peptides enumerated was compared to that of the peptide immunostimulant, tuftsin. All the peptides (upon intraventricular administration) with the exception of tuftsin affect the content of brain biogenic monoamines or their metabolites. Moreover, upon intravenous injection the neuropeptides under study except met-enkephalin exert a modulating action on the immune response pattern and intensity Leu-enkephalin, MIF and MAF have immunostimulant activity similar to tuftsin. TRH given in high doses (100 and 150 mg/kg) provokes almost a two-fold decrease in the antibody titer. This peptide has an immunosuppressant effect when administered both intravenously and intracisternally. It is suggested that neuro- and immunomodulator effects have much in common at the level of cell receptors.
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PMID:[Comparison of the neuro- and immunomodulator properties of low-molecular neuropeptides]. 612 28

Because of the enormous growth over the last three decades of research on the role of peptides in the brain, the need became apparent to determine the status of these compounds in terms of their current research interest. Since 1965, over a quarter of a million research papers have been published on peptides that have since been classified as neuroactive. The present study was undertaken to analyze systematically the yearly trends of research emphasis in neuroactive peptides as reflected by their individual frequency of publication by year, beginning in 1966. A computer analysis of the publication characteristics was carried out using the Medline data base in which the citation search was limited to the topic brain crossed with the topic mammal. One criterion for the inclusion of a given peptide in the analysis was a frequency of 25 or more citations following its discovery, as related to the mammalian brain. The 42 peptides that met this criterion were: adrenocorticotropic hormone, angiotensin II, atrial natriuretic factor, bombesin, bradykinin, calcitonin, calcitonin gene-related peptide, carnosine, beta-casomorphin, cholecystokinin, corticotropin-releasing factor, delta sleep-inducing peptide, dynorphin, beta-endorphin, Leu-enkephalin, Met-enkephalin, galanin, gastrin, glucagon, growth hormone, growth hormone-releasing factor, insulin, kyotorphin, beta-lipotropin, luteinizing hormone-releasing factor, melanocyte-stimulating hormone release inhibitory factor-1, alpha-melanocyte-stimulating hormone, motilin, neurokinin A, neurokinin B, neuropeptide Y, neurotensin, oxytocin, pituitary adenylate cyclase activating polypeptide, peptide HI, prolactin, secretin, somatostatin, substance P, thyroid-releasing hormone, vasopressin, and vasoactive intestinal peptide. An overall analysis of the 298,105 papers published on these 42 peptides since 1965 revealed that the research activity of 24,742, or 8.30%, of the studies, focused on their neuroactive properties. Taken as a whole, the research on neuroactive peptides reached a peak in 1986, as reflected by the total of 1793 papers published during that year. Although the level of publication has fluctuated between 1548 and 1774 research papers over the last 6 years, it is now clear that the trend in research on neuroactive peptides has reached an asymptote today that shows no sign of deviation. A temporal analysis year by year of individual publication profiles revealed three distinct trends: 1) peptides showed a slow development in research interest and did not exceed more than 15-30 publications per year; 2) peptides exhibited a steady increase in research activity over the years that continues today; and 3) peptides displayed an initial, often intense, research emphasis that inexplicably declined, in some cases precipitously, in the mid 1980s.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Neuroactive peptides: unique phases in research on mammalian brain over three decades. 800 41


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