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)

Two different classes of binding sites probably related to serotonergic receptors have already been reported: 5-HT1 binding sites recognize [3H]5-hydroxytryptamine with a high affinity (Kd = 3 nM) and S2 binding sites recognize [3H]spiroperidol and [3H]ketanserine. An additional population of sites has been observed in crude membrane preparations or fractions enriched with synaptosomal membranes obtained from rat brain cortex. This population was observed as a single class of sites in a synaptosomal fraction (L fraction--according to Laduron (1977)). It corresponded to a dissociation constant Kd = 13-15 nM, and Bmax = 0.80 +/- 0.15 pmol/mg protein. Displacement experiments showed that it recognized preferentially the 5-HT structure (bufotenin, 5-MeO-tryptamine). Tryptamine was a weak displacer and 5,7-dihydroxytryptamine totally inefficient. Neither 8-OH-DPAT, nor quipazine had any effect. Methiothepin, cinanserin and cyproheptadine displaced 5-HT from these sites whereas ergot derivatives did not. Contrary to 5-HT1 binding, this recently observed binding was not altered by GTP; alpha-MSH reduced the corresponding Bmax whereas Leu-enkephalin did not. The degenerative lesion of the serotonergic fibers led to a slight increase in the Bmax of the binding without altering the Kd which means that corresponding sites are not located on serotonergic fibers and might be postsynaptically located.
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PMID:Multiple high affinity binding sites for 5-hydroxytryptamine: a new class of sites distinct from 5-HT1 and S2. 405 78

1 Administration of the potent 5-hydroxytryptamine (5-HT) re-uptake inhibitor fluvoxamine (25 mg/kg i.p. for 14 days) to adult cycling female rats did not alter either the number of oestrous episodes or the plasma concentrations of luteinizing hormone determined on days 2, 9 and 14 of treatment. 2 Fluvoxamine (25 mg/kg i.p.) induced in male rats a clear-cut lowering of beta-endorphin-like immunoreactivity from the anterior pituitary, but not the neurointermediate lobe, and increased concomitantly plasma levels of beta-endorphin and beta-lipotropin. 3 Fluvoxamine (12.5 and 25 mg/kg i.p.) stimulated, although not strikingly, prolactin (PRL) secretion in adult male rats, and at 25 mg/kg i.p. potentiated the PRL-releasing effect of 5-hydroxytryptophan (30 mg/kg i.p.). 4 In male rats treated daily with fluvoxamine (25 mg/kg i.p.) the PRL-releasing effect of an additional acute fluvoxamine administration (same dose) was abolished after 4 days maintenance treatment. One week after withdrawal of maintenance, which had been given for 14 days, the challenge dose of fluvoxamine was still unable to raise plasma PRL levels. 5 The endocrine effects of acute fluvoxamine administration are compatible with activation of 5-HT neurotransmission in the central nervous system. The mechanism(s) underlying tolerance to the PRL-releasing action of the drug is presently obscure. Its elucidation should provide insight into the mechanism of action of antidepressant drugs affecting 5-HT function.
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PMID:Neuroendocrine studies with fluvoxamine: animal data. 613 46

The perfused, isolated, pituitary cell column was used to measure the release of alpha-melanotropin (alpha-MSH)-like immunoreactivity (LI), carboxyl terminal corticotropin (C-ACTH)-LI, gamma-lipotropin (gamma-LPH)-LI, alpha-endorphin-LI, beta-endorphin-LI and amino-terminal pro-opiocortin (N-POC)-LI from rat pars intermedia (PI) cells. Concomitant secretion of all PI peptides was observed during basal release and in response to all applied stimuli. Dopamine (DA) caused a dose-dependent (10(-9)-10(-5) M) simultaneous inhibition of peptide release which was antagonised by haloperidol. Isoprenaline stimulated the release of PI peptides in a parallel, dose-related (10(-10)-10(-6) M) manner and was blocked by propranolol. Stimulation of peptide secretion caused by low concentrations (10(-8) M), of adrenaline (AD) and noradrenaline (NA) changed to inhibition at high concentrations (10(-5) M) whereas intermediate concentrations (10(-6), 10(-7) M) possessed both inhibitory and excitatory effects. A 45 mM solution of K+ ions stimulated the release of PI peptides and both the K+-stimulated secretion and basal secretion were Ca++-dependent. MSH-release-inhibiting factor (MIF) and 5-hydroxytryptamine (5-HT) failed to alter peptide secretion from the perfused PI cells. We conclude that pro-opiocortin (POC) peptides are released concomitantly from rat PI cells and that biogenic amines are involved in their release.
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PMID:Secretion of pro-opiocortin peptides from isolated perfused rat pars intermedia cells. 613 22

1 Morphine and related synthetic surrogates as well as beta-endorphin and methionine enkephalin caused a contractile response of the longitudinal musculature of the terminal colon of Long Evans rats.2 The muscular contraction caused by the narcotic analgesics exhibited stereospecificity, with levorphanol being about 50 times more potent than dextrorphan and (-)-methadone 4 times more potent than (+)-methadone. In addition, the rank order in potency of a homologous series of N-alkyl substituted norketobemidones demonstrated that the activity of these compounds in eliciting contractile responses corresponded to that for analgesic efficacy in the rat and also correlated to the ability of these derivatives to inhibit the muscular twitch evoked by electrical stimulation of the guinea-pig ileum.3 Naloxone blocked the contractile response of the opiates following competitive kinetics; the naloxone pA(2) values for morphine, etorphine, levorphanol and methadone were very close, in spite of the marked differences in potency of these agents.4 The contractile effect of morphine on the rat colon was abolished by incubation of the tissues with tetrodotoxin 2.0 x 10(-7) M or by decreasing the external Ca(2+) level 100 fold. Increasing the external Ca(2+) concentration caused an apparent non-competitive antagonism of the response to morphine.5 Pretreatment of the tissues with hexamethonium 8.3 x 10(-5) M caused a modest antagonism of the morphine effect while atropine 5.8 x 10(-7) M did not significantly modify the morphine contractile effect. In contrast, methysergide 10(-5) M caused a 10 fold increase in the morphine EC(50).6 Colons from rats rendered tolerant-dependent on morphine were markedly less sensitive to the contractile effects of morphine than those from placebo-treated controls. Tolerance to morphine was also accompanied by an increased sensitivity to the contractile effects of 5-hydroxytryptamine (5-HT).7 A marked increase in the spontaneous muscular activity of segments of the terminal colon of rats chronically treated with morphine was found to occur upon removal of the residual morphine in the tissues by repetitive washings. The spontaneous activity was arrested by applications of morphine, suggesting that physical dependence can be demonstrated in vitro in this particular preparation.8 It is concluded that the opiate-induced contractile response is mediated via stereospecific, naloxone-sensitive, opiate receptors and that the muscular response involves the activation of a 5-HT neurone in the nerve terminals of the colon.
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PMID:Contractile effect of morphine and related opioid alkaloids, beta-endorphin and methionine enkephalin on the isolated colon from Long Evans rats. 617 Mar 77

Twenty-five endocrine tumors of the rectum (rectal carcinoids) were examined immunohistochemically for various pancreatic and gut neurohormonal polypeptides. Twenty-one of the tumors were found to contain cells displaying pancreatic polypeptide (PP), glucagon, somatostatin, insulin, substance P, enkephalin or beta-endorphin immunoreactivity. At least 11 of the tumors contained more than one peptide hormone. In some of the tumors PP cells made up the major cell population, in others the glucagon cells constituted the majority. Only four of the tumors contained 5-hydroxytryptamine. Rectal endocrine tumors seem unique among gut endocrine tumors in that they may store immunoreactive enkephalin, beta-endorphin and even insulin. None of the patients displayed the carcinoid syndrome; symptoms were usually vague and uncharacteristic. In many cases the tumor was found at routine examination.
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PMID:Immunohistochemical evidence of peptide hormones in endocrine tumors of the rectum. 617 Apr 21

Supra-ependymal nerves in mammals (mainly rats) have been shown to contain serotonin (5-hydroxytryptamine, 5-HT) by combined Falck-Hillarp fluorescence histochemistry, ultrastructural monoamine cytochemistry and pharmacology as well as by immunohistochemistry and autoradiography. Supra-ependymal 5-HT cells do not occur. At least in rats, virtually all supra-ependymal nerves contain 5-HT and in our opinion the occasionally described non-5-HT supra-ependymal nerve cells and their processes contribute little to the supra-ependymal nerve plexus (with the possible exception of those cells above the median eminence). The cells of origin of the supra-ependymal 5-HT nerves are situated in raphe nuclei. The axons and terminals (varicosities) contain small and large dense core vesicles in both of which 5-HT is stored. A co-transmitter has not been found among the candidates investigated so far (leu- and met-enkephalin, substance P and gamma-aminobutyric acid (GABA)). The nerves possess uptake mechanisms specific for 5-HT and possibly GABA. Occasionally desmosome-like junctions are observed between 5-HT nerve terminals and ependymal cells but no true synapses. The function of these nerves is not known. They do not appear to regulate ciliary movement, but might influence the shape of ependymal cells.
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PMID:Supra-ependymal serotoninergic nerves in mammalian brain: morphological, pharmacological and functional studies. 618 36

Peptide, 5-hydroxytryptamine (5-HT)-, tyrosine hydroxylase (TOH)-, and glial fibrillary acidic protein (GFAP)-like immunoreactivity was studied in the optic tectum of Rana pipiens. Peroxidase-antiperoxidase and indirect immunofluorescence single- and double-labeling methods were used to compare differential laminar distribution of each of these substances. Substance P (SP), leucine-enkephalin (LENK), cholecystokinin octapeptide (CCK8), bombesin (BOM), avian pancreatic polypeptide (APP), and possibly neurotensin display unique individual patterns of laminar distribution of processes and cell bodies throughout the tectum. A correlative analysis of the topographical distribution of SP, LENK, BOM, and APP on the basis of double-labeled sections shows a precise laminar segregation of these substances. Vasoactive intestinal peptide-, beta-endorphin-, and ranatensinlike immunoreactivity is consistently absent from our material. 5HT- and TOH-like immunoreactivity discloses a reticular array of fibers without clear evidence of laminar organization. This peptide-like laminar organization is particularly elaborate throughout the superficial neuropil of the optic tectum, the major retinorecipient zone. The pattern of lamination demonstrated in the present study differs in several important features from that previously described on the basis of several histological methods. The cells of origin of processes (axons and/or dendrites) in the superficial tectal neuropil may be either intrinsic or extrinsic to the tectum. Special reference is made to conflicting evidence regarding the possibility of a retinal contribution to peptide-like tectal lamination.
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PMID:Laminar organization of peptide-like immunoreactivity in the anuran optic tectum. 619 80

Characteristics of histamine (Hi) and 5-hydroxytryptamine (5-HT) release from rat peritoneal mast cells in response to the polypeptide adrenocorticotropin (ACTH) were studied. During a 15 min incubation at 37 degrees C, ACTH evoked Hi as well as 5-HT release from rat mast cells at concentrations of 1 X 10(-4) M-1 X 10(-3) M. The release was dose-dependent and very rapid. After 15 sec the amount of the amines released was the same as after 4.5 min. In most experiments, the percentage of Hi release was slightly but significantly higher than the percentage of 5-HT release. Hi and 5-HT release induced by ACTH also took place in a calcium-free medium. However, the release of the amines was decreased when calcium was omitted. Comparison of the effects of ACTH, compound 48/80 and substance P on mast cell secretion showed that ACTH is about 100 times less active then substance P which was in turn about 100 times less active than compound 48/80. When both ACTH and compound 48/80 were used together as liberators , the release was significantly higher than with either liberator alone. Our results indicate that there are receptor sites for the endogenous polypeptide ACTH on the mast cell membrane which mediate Hi and 5-HT release. This release was found to resemble that evoked by the basic secretogogue compound 48/80 but in some aspects to be different from that evoked by substance P.
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PMID:The effect of adrenocorticotropin on histamine and 5-hydroxytryptamine secretion from rat mast cells. 620 67

Effects of neuroactive peptides on the release of labeled 5-hydroxytryptamine (5-HT) from preloaded rat spinal cord slices were investigated. The 5-HT release was significantly stimulated by somatostatin (10-50 microM) and substance P (10-50 microM), but not by neurotensin (50 microM), beta-endorphin (30 microM) and methionine-enkephalin (met-enk) (100 microM). Somatostatin-stimulated 5-HT release was markedly inhibited by gamma-aminobutyric acid (GABA) (30 microM), but not by baclofen (30 microM) and met-enk (100 microM). Substance P-stimulated 5-HT release was strongly inhibited by GABA (30 microM) and baclofen (30 microM), but not by met-enk (100 microM). High concentrations (20 mM) of potassium also stimulated 5-HT release. The high potassium-stimulated 5-HT release was not affected by GABA (30 microM) and met-enk (100 microM). These results suggested further evidence on the important role of somatostatin and substance P as modulators of serotonergic neurones.
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PMID:Effect of neuroactive peptides on labeled 5-hydroxytryptamine release from rat spinal slices in vitro. 620 42

1 The spasmogenic and spasmolytic effects of beta-lipotropin (LPH) fragments and one analogue were investigated on different parts of the gastro-intestinal tract of guinea-pig and rat in vitro.2 Changes in muscle tone were observed in colon and rectum and to a lesser extent in jejunum and ileum of both species. Rat colon and rectum contracted to the peptides. Guinea-pig colon and rectum relaxed after an initial short-lasting contraction.3 On the rat rectum (D-ala(2))met-enkephalin, leu-enkephalin, gamma-endorphin, alpha-endorphin and beta-LPH 80-91 caused dose-dependent contractions, their ED(50) values being 0.96 x 10(-12) mol, 1.05 x 10(-11) mol, 1.22 x 10(-11) mol, 1.08 x 10(-10) mol, 2.65 x 10(-10) mol and 6.5 x 10(-9) mol, respectively.4 Naloxone dose-dependently shifted the dose-response curve of met-enkephalin to the right. Atropine, hexamethonium, burimamide, mepyramine, propranolol and indomethacin did not influence the response to met-enkephalin.5 In the presence of tetrodotoxin, the ED(50) for met-enkephalin and the maximal contractor response induced by met-enkephalin, appeared to be increased.6 The 5-hydroxytryptamine (5-HT) antagonists, methysergide and cyproheptadine, reduced the contractor response in a non-competitive manner. The alpha-adrenoceptor antagonist phentolamine, in contrast, caused an increase of the maximal response to met-enkephalin of up to 200%. Noradrenergic and tryptaminergic systems, therefore, might be involved in the changes in muscle tone induced by met-enkephalin.7 These results demonstrate that rectum and colon of guinea-pig and rat are very sensitive to opioid-like peptides.
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PMID:Effects of endorphins on different parts of the gastrointestinal tract of rat and guinea-pig in vitro. 624


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