UNIPROT:P01178 - FACTA Search

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Query: UNIPROT:P01178 (oxytocin)
15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Extracellular recordings were made from 297 spontaneously firing neurones in the dorsal motor nucleus of the vagus (DMV) in slice preparations of rat medulla oblongata. Some of the neurones recorded were identified to be vagal motoneurones by antidromic stimulation. The cells fired with a slow irregular pattern at an average rate of 1.1 +/- 0.1 spikes/s (mean +/- S.E.M.). 2. Arginine vasopressin (AVP) was applied by perfusion in 196 of the 297 cells. Most of the neurones (190/196, 97%) were excited by 10(-6) M AVP with an increase in firing rate from the basal level of 1.1 +/- 0.1 to a maximum of 2.5 +/- 0.2 spikes/s. There was a dose-dependent relation between the concentration of AVP and the increased firing rate in all DMV neurones tested (n = 38). The threshold concentration of the peptide to produce changes in firing rate was assumed to be about 10(-10) M. The remaining six neurones were not affected by application of AVP. 3. Application of oxytocin (OXT, 10(-6) M) increased the firing rate of all thirty-eight neurones tested. The effects of AVP and OXT on all neurones examined (n = 20 and 4, respectively) still persisted after blocking the synaptic transmission in a low-Ca2+ or Ca(2+)-free-high-Mg2+ solution, indicating the direct action of both AVP and OXT on the postsynaptic membranes. 4. The AVP-induced excitatory responses were completely but reversibly blocked by the V1-type receptor antagonists, [1-(beta-mercapto-beta, beta-cyclopentamethylene-propionic acid), 2-(O-methyl)tyrosine]-arginine vasopressin (d(CH2)5Tyr(Me)AVP) (n = 5) and Phaa-D-Tyr(Et)Phe-Gln-Asn-Lys-Pro-Arg-NH2 (n = 6), whereas a selective and reversible OXT receptor antagonist, desGly-NH2d(CH2)5[Tyr-(Me)2Thr4]ornithine vasotocin, which suppressed the OXT-induced excitation, did not block the responses to AVP (n = 11). 5. Application of angiotensin II (AII, 10(-6) M) to 153 neurones increased the firing rates of 60 (39%) neurones. The firing rate was increased from the basal level of 1.0 +/- 0.1 to a maximum of 1.8 +/- 0.2 spikes/s (n = 60). The effect of AII was completely abolished by an AII receptor antagonist, [Sar1,Ile8]angiotensin II (n = 6). There was a dose dependence of the excitatory response on AII concentration in all of eleven neurones tested. The threshold concentration was assumed to be about 10(-9) M. The activity of 5 (3%) of 153 neurones was decreased, and the remaining 88 (58%) neurones were not affected by AII.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of vasopressin and angiotensin II on neurones in the rat dorsal motor nucleus of the vagus, in vitro. 130 79

In order to determine the strain differences in learning of swimming behavior and to study the influence of vasopressin or its derivatives on hemicholinium-3-induced impairment of water maze learning in mice, we designed a new apparatus using water maze which has three panels in small fish breeding water bath (L60 x W30 x H36 cm). In the first swimming, six strains of adult male mice, ICR, ddY, ddN, C3H/He, BALB/C and C57BL were subjected to learn swimming behavior twice a day for 6 d in a straight course. Only ICR, ddN, C57BL and BALB/C strain mice were chosen for the next experiment. In the second swimming, mice (ICR, ddN, C57BL, BALB/C) were swum in the water maze apparatus. Scopolamine-induced impairment of water maze learning was produced only in ICR, BALB/C mice, but not in C57BL and ddN strain, which was recovered by physostigmine. Amnesia was not obtained by intracerebroventricular injection (i.c.v.) of cycloheximide and AlCl3 in mice (ICR). Hemicholinium-induced amnesia was improved by vasopressin and desmopressin. Lysine-vasopressin and oxytocin were without affecting hemicholinium-induced amnesia. Pretreatment with a vasopressin antagonist, ([1-(beta-mercapto-beta,beta-cyclopenta-methylene propionic acid), 2-(o-methyl)tyrosine arginine]-vasopressin) resulted in a reversible effect on the improvement of hemicholinium-induced amnesia by vasopressin. Of four different strain mice, ICR mice were the most preferable to the presently used test. They were also more responsive to hemicholinium and vasopressin than the other strains. These results suggest that the simple water maze apparatus may be useful for a pre-examination of nootropics or a study of learning of swimming behavior in mice.
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PMID:[Strain differences of mice in learning of swimming behavior and effect of hemicholinium and vasopressin. Observation by a simple water maze apparatus]. 148 47

The distribution and properties of nonapeptide binding sites in the kidney of the anuran Xenopus laevis were investigated using quantitative in vitro autoradiography. The binding studies were performed with [3H]arginine vasopressin (AVP) as ligand because [125I]arginine vasotocin (AVT) lacks biological activity. Specific binding sites for [3H]AVP are located in the glomeruli of the kidney. [3H]AVP binding results in a steady state of association and dissociation between ligand and binding sites. Scatchard and Hill analyses of saturation experiments showed that [3H]AVP binds to a single class of binding sites with a dissociation constant (Kd) of 430 +/- 109 pM and a maximum binding capacity (Bmax) of 5.306 +/- 1.379 fmol/mm2 (n = 8). Displacement studies demonstrated the same affinity of these [3H]AVP binding sites to [3H]AVP, unlabeled AVP, and AVT, whereas mesotocin possesses only weak affinity. Further nonapeptides like oxytocin and isotocin or the mammalian-specific V1 receptor antagonist [1-beta-mercapto-beta,beta-cyclopentamethylene propionic acid)-2-(O-methyl)-tyrosine)-AVP or the V2 receptor agonist (1-deamino-8-D-arginine)-vasopressin or unrelated peptides did not alter the binding of [3H]AVP. The localization of nonapeptide binding sites in the glomeruli with the same affinity to AVP as to AVT agrees with the finding that AVT causes antidiuresis in Xenopus laevis. An earlier study demonstrated Xenopus laevis interrenal tissue to possess a higher sensitivity for AVT than AVP which points to a nonapeptide receptor with a higher affinity for AVT than AVP.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization and quantification of nonapeptide binding sites in the kidney of Xenopus laevis: evidence for the existence of two different nonapeptide receptors. 156 20

The present study was designed to determine the localization of the endometrial oxytocin receptor during the ovine oestrous cycle, particularly on day 14, the time of initiation of luteal regression in the ewe. Samples were obtained from 29 ewes at different stages of the oestrous cycle (several during the luteal phase and on every day between day 14 (-2) and day +3 of the oestrous period). Oxytocin receptors were localized autoradiographically in sections of uterine tissue, using the 125I-labelled oxytocin receptor antagonist [1-(beta-mercapto-beta, beta-cyclopentamethylene propionic acid), 2-(ortho-methyl)-Tyr2,Thr4,Orn8, Tyr9-NH2]-vasotocin (125I-labelled OTA). There was some variation in the pattern of 125I-labelled OTA labeling between different uterine tissue samples from the same ewe and also between samples obtained from different ewes thought to be at the same stage of the oestrous cycle. A clear overall pattern did, however, emerge with 125I-labelled OTA-binding sites distributed between luminal epithelial cells, glandular epithelial cells and caruncular stromal cells to varying extents on different days of the cycle. During the luteal phase (days 5-12) clear specific labelling of endometrial tissue was generally absent. On day 14 labelling was evident on the luminal epithelium, but only in nine tissue samples out of a total of 18 studied, indicating that the entire luminal surface did not contain oxytocin receptors at this time. Between the day before oestrus and day 3 of the oestrous cycle the luminal epithelium was consistently labelled.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Autoradiographic localization of oxytocin receptors in the endometrium during the oestrous cycle of the ewe. 165 40

The ability of vasopressin to elevate cytosolic Ca2+ in small cell lung cancer (SCLC) cells was investigated. Ten nanomolar vasopressin elevated the cytosolic Ca2+ in 6 of 8 SCLC cell lines that were loaded with Fura-2 AM. Using SCLC cell line NCI-H345, the effect of vasopressin was dose dependent, being maximal at 100 nM, where the cytosolic Ca2+ was elevated from 150 to 210 nM. Because addition of 1 mM EGTA had no effect on the vasopressin response, vasopressin released Ca2+ from intracellular pools. Also, oxytocin weakly elevated the cytosolic Ca2+. The response to vasopressin was strongly blocked by [(beta-mercapto-beta,beta-cyclopentamethylene propionic acid)1,O-MeTyr2,Arg8]vasopressin and weakly blocked by [(beta-mercapto-beta,beta-cyclopentamethylene propionic acid)1,O-MeTyr2,Orn8]vasotocin. These data suggest that V1 vasopressin receptors are present on SCLC cells.
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PMID:Vasopressin elevates cytosolic calcium in small cell lung cancer cells. 172 21

Some of the binding characteristics of a novel oxytocin receptor ligand 125I-labelled [1-(beta-mercapto-beta, beta-cyclopentamethylene propionic acid), 2-(ortho-methyl)-Tyr2,Thr4,Orn8,Tyr9-NH2]-vasotocin ([125I]OTA) have been determined in the sheep uterus. The compound was subsequently used for the autoradiographic localization of oxytocin receptors in the uterus and oviduct of the ewe. Specific binding of [125I]OTA to crude membrane fractions of ovine endometrium was time-dependent and was unaffected by the addition of cations to incubation media. Endometrial membranes contained a single population of saturable, high-affinity binding sites for the iodinated ligand (dissociation constant (Kd) 0.23 +/- 0.08 nmol/l) and unlabelled oxytocin competed with [125I]OTA for binding sites with high affinity (Kd 1.29 +/- 0.4 nmol/l) in the presence of Mg2+ In contrast, unlabelled OTA was able to compete with high affinity (Kd 1.13 +/- 0.16 nmol/l) in the absence of cation. Competition studies with a number of oxytocin analogues and related peptides and the tissue distribution of [125I]OTA binding sites also indicated that [125I]OTA bound to the ovine oxytocin receptor. This was further validated by autoradiographic studies which showed specific labelling with [125I]OTA to be greater to uterus and oviduct obtained from ewes which had been killed within 2 days of oestrus than to similar tissue from ewes killed during the luteal phase. In both the ampullary and isthmic regions of the oviduct and the myometrium, [125I]OTA binding sites were confined to smooth muscle. Endometrial binding sites for [125I]OTA were consistently located on the luminal epithelium and epithelial cells lining secretory glands.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization and localization of oxytocin receptors in the uterus and oviduct of the non-pregnant ewe using an iodinated receptor antagonist. 184 84

Structural and dynamic properties of [8-arginine]vasopressin and a class of highly potent vasopressin V1 antagonists which contain 3-mercapto-3,3-cyclopentamethylene propionic acid (Mca) in position 1 of the vasopressin sequence have been determined. On the basis of two-dimensional NMR experiments in dimethyl sulfoxide solution, interproton distances were derived according to which model conformations were built and refined using molecular dynamics simulations. The conformation of vasopressin and the V1 antagonists differ mainly in the region of the mutated residue. The antagonistic property was found to be related to an inversed chirality of the disulfide bridge. In all investigated molecules, characteristic beta-turn structure elements were found for the backbone conformation of the endocyclic residues Tyr2-Asn5. For this portion of the peptide sequence, various conformational equilibria were detected which matched different time scales. For [Arg8]vasopressin, averaged NMR parameters were obtained which could be explained by rapid interconversion between different beta-turn geometries, whereas multiple slowly exchanging conformations were observed for the V1 antagonists. V1 antagonists containing sarcosine in position 7 exhibited multiple spectral patterns for the exocyclic part attributed to cis/trans isomerization. The X-ray structure of deamino-oxytocin [Wood, S. P., Tickle, I. J., Treharne, A. M., Pitts, J. E., Mascarenhas, Y., Li, J. Y., Husain, J., Cooper, S., Blundell, T. L., Hruby, V. J., Buku, A., Fischman, A. J. & Wyssbrod, H. R. (1986) Science 232, 633-636] was found to represent one sample of the conformational space covered by the multiple conformations found for [Mca1, Arg8]vasopressin.
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PMID:Conformation of [8-arginine]vasopressin and V1 antagonists in dimethyl sulfoxide solution derived from two-dimensional NMR spectroscopy and molecular dynamics simulation. 193 33

The influence of arginine vasotocin (AVT) on the interrenal secretion of the clawed toad (Xenopus laevis) was studied combining in vivo and in vitro experiments. In vivo: A single injection of 3 nmol AVT per 100 g body weight was given, and the concentrations of corticosterone and aldosterone in the serum were measured after 1, 3, 6, 12, and 24 hr. The serum levels of both steroids remained elevated over 6 hr and declined to normal levels within 12 hr. The increase of the aldosterone concentration was relatively stronger than that of corticosterone. In vitro: A perifusion system was used to study the influence of AVT concentrations ranging from 0.1 to 50 nM on the secretion rates of corticosterone and aldosterone. The response of the interrenals was dose dependent; corresponding to the in vivo results, the elevation rate was higher for aldosterone than for corticosterone. The effects of several nonapeptides were compared. AVT was most effective, followed by mesotocin and arginine vasopressin (AVP). Isotocin and oxytocin had less effect. The selective agonist of the mammalian V2 receptor (1-deamino-8-D-arginine)-vasopressin (DDAVP) did not stimulate the interrenals, while the V1 receptor-selective antagonist ((1-beta-mercapto-beta,beta-cyclopentamethylene propionic acid)-2-(O-methyl)-tyrosine)-AVP could not diminish the stimulation by AVT. Thus, the AVT receptor of the amphibian interrenal must be a special one and is different from the V1 and V2 types of mammals. In a comparison of the effects of AVT with other stimulators such as ACTH(1-28) or urotensin II, it was found that the sensitivity of the interrenals to AVT was similar to that of these peptides. The results indicate that AVT plays an important role in the osmomineral regulation of Xenopus laevis by acting on the corticosteroid secretion of the interrenals.
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PMID:Neurohypophysial hormones and steroidogenesis in the interrenals of Xenopus laevis. 196 9

The roles of oxytocin (OT) and vasopressin (AVP) on both basal and estrogen-induced prolactin (PRL) secretion were examined. Adult female Sprague-Dawley rats that were ovariectomized for 3 weeks and received estrogen treatment for 1 week were used. Intravenous administration of hormones and serial blood sampling were accomplished through indwelling intraatrial catheters which were implanted two days before. Plasma PRL levels were measured by radioimmunoassay. Oxytocin at a dose of 20 micrograms/rat stimulated a moderate PRL release in the morning and lower doses (5 and 10 micrograms) were without effect. Vasopressin was most effective at a dose of 5 micrograms/rat in stimulating PRL release, while consecutive injections of higher doses (10 and 20 micrograms) were less effective. In contrast, TRH, ranging from 1 to 8 micrograms/rat, induced a dose-dependent increases in PRL secretion. Using the effective dosages determined from the morning studies, repeated injections of either OT, AVP or their specific antagonists MPOMeOVT [( 1-(beta-mercapto-beta, beta-cyclopentamethylene propanoic acid), 2-(O-methyl)tyrosine, 8-ornithine]-vasotocin) and d (CH2)5Tyr(Me)AVP ([1-(beta-mercapto-beta, beta-cyclo-pentamethylene propionic acid), 2-(O-methyl)tyrosine, 8-arginine]-vasopressin), were given hourly between 1300 to 1800 h and blood samples were obtained hourly from 1100 to 1900 h. It was found that either OT or AVP significantly reduced the afternoon PRL surge, while their antagonists were not as effective. When OT or AVP were administered together with their specific antagonists, the inhibitory effects of either hormone on PRL surge were reversed. Thus it is concluded that both OT and AVP assume a non-specific stress-like effect on PRL release, in which basal secretion is stimulated and surge secretion is inhibited.
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PMID:Paradoxical effects of oxytocin and vasopressin on basal prolactin secretion and the estrogen-induced prolactin surge. 212 15

The effects of metaphylactic measures in cattle herds with the aim of diminishing puerperal disturbances and ensurement of high reproductive performance were studied. About 5000 cows in more than 30 groups (experimental and controls) were included into the clinical investigations. Dietary supplementation by sodium propionic acid over a period of 4 weeks, oxytocin or parasympathomimetics administered during the first 3 days post partum had a certain metaphylactic effect, only when the therapeutic principle met the prevalent cause of the given puerperal disturbance. In herds with high incidence of noninfectious retention of fetal membranes the metaphylactic application of Se and Vitamin E (10 days ante partum) can be taken into account. Stimulation of the ovarian activity by GnRH is recommended in animals which fail to have developed follicular activity by the 12th-15th day post partum.
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PMID:[Metaphylaxis of puerperal disorders in cattle]. 224 74

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