Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vasopressin produced analgesia in mice as estimated by using abdominal constriction tests (ED50 8.5 micrograms/kg i.v.) or hot plate method (ED50 63 micrograms/kg i.v.). However, vasopressin (10 micrograms/kg i.v.) produced no depression of locomotor activity in mice. Vasotocin had slight analgesic action; oxytocin or norepinephrine had none and there was no direct correlation between pressor response and analgesia. The analgesic action was nonopiate in nature as it was uninfluenced by the narcotic antagonist naltrexone at 5 to 15 mg/kg, but it was reserved by a vasopressin antagonist. Intraventricular administration of vasopressin (1-10 micrograms/kg) to mice produced no significant analgesia, suggesting a primarily peripheral locus of analgesic action. Vasopressin may play a role as an endogeneous pain regulating substance.
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PMID:Characterization of vasopressin analgesia. 705 94

Prolactin-releasing (PRF) activity was found in Pitressin (a commercial extract from posterior pituitary for vasopressin). Injection of Pitressin into conscious free-moving rats implanted with a permanent atrial indwelling cannula, produced a transient increase in prolactin concentration in the circulation. In order to find out whether the PRF activity was due to vasopressin or to an unidentified component in the Pitressin, we tested synthetic lysine vasopressin and demonstrated that vasopressin (1 U/kg) elevated plasma prolactin concentration about threefold. In contrast, oxytocin (1 U/kg) did not alter the prolactin concentration. In order to find out whether the effect of vasopressin is a direct or indirect action, we tested the vasopressin effect on hypophysectomized rats which had previously been implanted with 2 adenohypophyses under the kidney capsule. Again this dose (2 U/kg) of vasopressin elevated circulating plasma prolactin. These experiments indicate that vasopressin can elevate circulating prolactin concentration in nonestrogen-primed normal male rats and that vasopressin also stimulates prolactin secretion from transplanted glands dissociated from direct hypothalamic control.
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PMID:Vasopressin has a direct effect on prolactin release in male rats. 705 60

Vasotocin (VT)- and neurophysin (NP)-synthesizing neurons were demonstrated by immunocytochemistry in the diencephalon of the pigeon, Columba livia. Three diencephalic regions contain VT-NP cells: (1) periventricular preoptic area and hypothalamus, including nucleus periventricularis magnocellularis (PVM); (2) lateral preoptic area and hypothalamus; and (3) dorsal diencephalon. The immunoreactive cells in each of these three regions were divided into groups based on cytology and topography. No differences were found in the location of VT and NP cell groups. The periventricular region contains three continuous cell groups (P1-P3) extending from the posteroventral preoptic area to the anterodorsal hypothalamus and PVM. The lateral region has two cell groups composed of medium- to large-sized cells associated with the quintofrontal tract (L1) or with the optic tract (L2), while a third group (L3) lies between these two cell groups. Two accessory cell groups reside in the dorsolateral hypothalamus; L4 contains scattered cells of varied size, whereas L5 has small- to medium-sized cells clumped together. The dorsal diencephalic cell groups are found in the following locations: (1) lateral and dorsal to the lateral forebrain bundle (DD1); (2) in the area ventral to the dorsomedial anterior thalamic nucleus and dorsolateral to PVM (DD2); and (3) at the dorsolateral border of nucleus rotundus (DD3). To avoid potentially inaccurate mammalian homologies, the cell group nomenclature denotes topographic position. Nevertheless, the presence of VT-NP cells in PVM and projections to the brainstem and spinal cord suggest a homology between PVM and some of the parvocellular subnuclei of the mammalian paraventricular nucleus.
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PMID:The localization of vasotocin and neurophysin neurons in the diencephalon of the pigeon, Columba livia. 706 40

[Arg8]Vasotocin (AVT) is considered to be the most primitive known vertebrate neurohypophyseal peptide of the vasopressin/oxytocin hormone family and may thus be ancestral to all the other vertebrate peptide hormones. The molecular evolution of the corresponding receptor family has now been studied by cloning an AVT receptor, consisting of 435 amino acid residues, from the teleost fish, the white sucker Catostomus commersoni. Frog oocytes injected with the AVT receptor-encoding cRNA respond to the application of AVT, but not to its structural and functional counterpart isotocin, by an induction of membrane chloride currents indicating the coupling of the AVT receptor to the inositol phosphate/calcium pathway. The pharmacological properties of the expressed AVT receptor show that it represents, or is closely related to, an ancestral nonapeptide receptor: oxytocin, aspargtocin, mesotocin, and vasopressin activated the receptor, but other members of the vasopressin/oxytocin family tested showed little or no potency; antagonists of the mammalian vasopressin V1 and oxytocin receptors blocked the AVT response. Comparison of AVT receptor sequences spanning transmembrane domains two to five, deduced by cloning cDNAs from the Pacific salmon Oncorhynchus kisutch, the cave-dwelling fish Astyanax fasciatus, and the anuran Xenopus laevis, with those of their mammalian counterparts emphasizes amino acid residues that are involved in hormone binding. The presence of a 5.0-kb transcript in various teleost tissues (pituitary, liver, gills, swim bladder, and lateral line) points to a physiological role for the fish AVT receptor in metabolic, osmoregulatory, and sensory processes.
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PMID:Structure, function, and phylogeny of [Arg8]vasotocin receptors from teleost fish and toad. 750 69

Cockerels with permanent cannulas in the brachial artery and vein were put into isolated slings. Arterial pressure and heart rate were continuously recorded. Following habituation, tests were initiated. In each cockerel 2 nmol/kg of the tested neurohypophysial peptide (NPs) or analogue was IV injected six times at 6-min intervals. Arginine vasotocin (AVT) caused an immediate vasodepressor (VDP) effect and tachycardia. These subsided within 20-30 s and were followed by a vasopressor (VP) response and bradycardia. On repeated injections of AVT, the VDP response declined and bradycardia intensified. Arginine vasopressin (AVP), oxytocin (OT), and mesotocin (MT) had short-lasting VDP effect in the following order of potency: OT = MT > AVT > AVP. Only AVT and, more effectively, AVP, caused a VP response. The VDP effect of MT and OT declined on repeated injections. When AVT was injected after three injections of MT, it had mostly an immediate VP effect. Although the V1 agonist is VP in chickens, at the dose used the V1 antagonist, [d(CH2)5,O-Me-Tyr2]AVP, had no effect on cardiovascular responses to AVT. Pretreatment with OT antagonist, [d(CH2)5-O-Me-Tyr2-Thr4.Tyr9.Orn8]VT, abolished the VDP effect of all NPs. Thus, MT had no effect on blood pressure, whereas AVP and, more effectively, AVT, had a marked immediate VP action. In chickens the VDP effect of NPs is probably mediated by an OT/MT-like receptor, wherein the peptide's ring structure, shared by AVT, OT, and MT, is important.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oxytocin antagonist blocks the vasodepressor but not the vasopressor effect of neurohypophysial peptides in chickens. 770 Aug 44

Using rabbit amnion membranes devoid of arginine vasopressin receptors, we have shown that arginine vasopressin acts as a partial agonist and oxytocin antagonist. We examined peptides with modifications in position 8 to determine the basis for partial agonism/antagonism. The 8-thioanalog of oxytocin had about 40% of oxytocin activity in eliciting PGE2 release by amnion cells and a corresponding 40% affinity for oxytocin binding sites on amnion membranes. Arginine vasotocin, which has arginine at the position 8 and about 90% homology with arginine vasopressin also acted as a full agonist. These results suggest that determination of the oxytocin antagonist activity of arginine vasopressin is largely dependent on the amino acid at position 3. We also synthesized the 8-thioanalog of arginine vasopressin, which had a very low affinity for arginine vasopressin binding sites in rat liver (V1 receptors) and rat kidney medulla (V2 receptors) membranes. These findings suggest that arginine vasopressin receptors are much more sensitive to modifications of the peptide bond between positions 8 and 9 than are oxytocin receptors.
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PMID:Arginine vasopressin antagonism of oxytocin-stimulated PGE2 release from rabbit amnion cells and the activities of thioanalogs of oxytocin and arginine vasopressin. 789 30

Vasotocin receptors were investigated in glomeruli and nephron segments microdissected from collagenase-treated kidneys of Rana ridibunda, using [d(CH2)5Tyr(Me)2,Thr4,Orn8,125I-Tyr-NH2(9)]vasotocin (125I-OVTA) as a radioligand. Specific 125I-OVTA binding sites were found only in glomeruli and not in all tubule segments tested. Glomerular receptors exhibited the following stereospecificity for recognition of vasotocin analogues: Tyr-NH2(9)-LA-V1a > 125I-OVTA > arginine vasotocin (AVT) > or = [d(CH2)5Tyr-(Me)2]AVP > OVTA > or = [Phe2,Orn8]VT > oxytocin (OT) > or = [d(CH2)5-Sar7]AVP > desGly9[d(CH2)5Tyr(Et)2]VAVP > or = [d(CH2)5Tyr(Et)2]VAVP > AVP > [1-desamino-8-D-arginine]vasopressin (DDAVP) > [Thr4,Gly7]OT. In addition, vasotocin enhanced [3H]inositol phosphate production in sieved glomeruli labeled with myo-[3H]inositol; the rank order of structural vasotocin analogues for stimulation of phosphoinositidase C was [Phe2,Orn8]VT > AVT > OT > AVP > DDAVP, whereas [Thr4,Gly7]OT was almost inactive, and the rank order of antagonists for inhibition of hormone-induced enzyme activation was Tyr-NH2(9)-LA-V1a > [d(CH2)5Tyr(Me)2]AVP = OVTA > [d(CH2)5Sar7]AVP > [d(CH2)5Tyr(Et)2]VAVP > or = desGly9[d(CH2)5Tyr(Et)2]VAVP. Results indicate that the 125I-OVTA-labeled binding sites detected in frog glomeruli reveal the pharmacological properties of mammalian V1b-pituitary vasopressin receptors and might be physiological vasotocin receptors involved in phosphoinositidase C stimulation.
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PMID:Frog glomerular vasotocin receptors resemble mammalian V1b receptors. 797 46

1. The neurohypophysial osmoregulatory hormones of the African toad Bufo regularis, a species adapted to estivate under dry and hot conditions, have been investigated. Vasotocin and hydrin 2 (vasotocinyl-Gly) have been identified by their retention times in high-pressure reverse-phase liquid chromatography and coelution with synthetic peptides, their pharmacological properties (vasotocin) and microsequencing. 2. Vasotocin-associated neurophysin (MSEL-neurophysin type) has been characterized by its N-terminal amino acid sequence. 3. In toads subjected to dehydration by evaporation (20% weight loss) or to osmotic stress by immersion in 2% NaCl for 3 hr (6% weight loss), the molar ratio hydrin 2/vasotocin (about 2:1) remained similar to the one observed in control animals. 4. In toads exposed to saline solution, there was a large decrease (roughly 30%) in the amounts of both hormones in the neuro-hypophysis. Environmental conditions for distinct secretions of vasotocin and hydrin 2 remain to be found.
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PMID:Vasotocin and hydrin 2 (vasotocinyl-Gly) in the African toad Bufo regularis: study under various environmental conditions. 809 51

The neurohypophysial hormones contained in the neurointermediate lobe of the pituitary of the Australian lungfish Neoceratodus forsteri have been investigated. Mesotocin was identified by coelution with the synthetic peptide in high-pressure liquid chromatography, by Edman amino acid sequencing, by mass spectrometry, by C-terminal sequencing through carboxypeptidase Y, and cleavage with prolyl endopeptidase. Vasotocin, if present, would be in very small amounts and hydrins were not detected. Oxytocin appears absent. Although Neoceratodus and Protopterus have different habitats, the former being permanently aquatic, the latter burrowing during estivation, the proportions of neurohypophysial hormones stored in neurohypophysis were roughly similar in the two species and not apparently affected by environmental conditions.
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PMID:Lungfish neurohypophysial hormones: chemical identification of mesotocin in the neurointermediate pituitary of the Australian lungfish Neoceratodus forsteri. 822 76

The neurohypophysial hormones of the ratfish (Hydrolagus colliei), a species belonging to the subclass Holocephali of cartilaginous fishes, have been investigated. An oxytocin-like hormone has been isolated from acetone-desiccated pituitary glands by using successively molecular sieving and high-pressure liquid chromatography. The peptide has been identified as oxytocin by coelution with synthetic oxytocin in HPLC, amino acid sequencing, mass spectrometry, and C-terminal sequencing through carboxypeptidase Y. Vasotocin may be present in a very small amount. Cartilaginous fishes appear to display a great diversity in their oxytocin-like hormones since five different peptides have been identified in rays and sharks that belong to the second subclass Selachii.
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PMID:Chemical identification of the mammalian oxytocin in a holocephalian fish, the ratfish (Hydrolagus colliei). 828 75


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