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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Persistent tubal pregnancy may be manifest by either acute symptoms or a persistent or rising beta-hCG titer following conservative surgery. This condition is a relatively new complication, related to the recent practice of conservative surgical management of tubal pregnancy. Much has been written on the identification and possible therapy for this condition but little is known about its pathophysiology. Eight cases of persistence were studied, as well as three cases of failed conservative procedures. In nine instances, the surgeon had concentrated appropriately on the maximally dilated portion of the tube, which contained the blood clot and aborted products of conception. Unfortunately, the implantation site was located medially, toward the uterus. Ways of avoiding this complication include medial exploration or possibly the use of mesosalpingeal injection of vasopressin. An understanding of the natural history of the pathologic process might also be valuable in the management of cases of "persistence" identified solely by a continuing beta-hCG titer.
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PMID:Persistent tubal pregnancy. 198 90

Patient preparation and a modified operative technique are described for electrocoagulation ablation of the endometrium using a roller-bar electrode. No preoperative or postoperative endometrial suppression was used. Rather, the endometrial cavity was denuded by suction curettage just before ablation, which was performed in the early proliferative phase of the menstrual cycle. Lidocaine paracervical block containing vasopressin was injected at the start of the procedure to control pain and to minimize bleeding and irrigation fluid absorption. Pulsed irrigation of the uterus was used to improve visibility through uterine debris and the bubbles generated by the electrical current. The first 20 patients who had electrocoagulation ablation of the endometrium with these modifications were compared with the first 18 patients who had laser coagulation ablation using standard technique and preoperative endometrial suppression. Compared with the laser method, the modified coagulation method resulted in a comparable rate of satisfactory bleeding decrease at 6 months (90 versus 94%), but involved a clinically significant reduction in total anesthesia time (66.8 versus 117.3 minutes) and volume of irrigation fluid used (5.7 versus 15.9 L).
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PMID:Modified endometrial ablation: electrocoagulation with vasopressin and suction curettage preparation. 203 Aug 76

The distribution and the amount of [3H]oxytocin binding were studied in the brain of adult rats of either sex, as well as in male and female castrates, some of which received injections of estradiol or testosterone. Intact males were treated with an aromatase inhibitor. Castration and inhibition of aromatase activity reduced, whereas estradiol and testosterone increased oxytocin binding, particularly in regions of the brain assumed to be involved in reproductive functions, such as the ventrolateral part of the hypothalamic ventromedial nucleus and the islands of Calleja and neighbouring cell groups. Binding of oxytocin to the uterus was also estrogen-dependent. In the same animals, we also studied the distribution of [3H]vasopressin binding sites present in the brain. It was similar in males and females, and was not affected by experimentally manipulating gonadal hormone levels. In immunocytochemical studies we noticed, as others had previously, that the vasopressin content of certain areas of the rat brain was affected by castration, whereas the oxytocin innervation was not. These results are discussed in relation to the possible functions of oxytocin in the brain and of the lack of correspondence between the immunocytochemical and the autoradiographic data.
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PMID:Gonadal steroids regulate oxytocin receptors but not vasopressin receptors in the brain of male and female rats. An autoradiographical study. 215 53

The binding of 3H-oxytocin (3H-OT) and 3H-arginine-vasopressin (3H-AVP) and the displacement from binding sites by four oxytocin analogues were studied in myometrial membrane preparations from full-term pregnant women. Specific 3H-OT binding was saturable with a maximal binding capacity of 76.1 fmol/mg DNA, and a dissociation constant of 0.5 pM. Corresponding values regarding 3H-AVP was 148.6 fmol/mg DNA and 0.7 pM. The oxytocin analogues tested demonstrated a high specific binding to the OT and AVP receptor sites; in fact, the affinity of the analogues to the 3H-AVP binding sites was higher than to the 3H-OT binding sites. The order of potency between the analogues was CAU greater than CAM greater than CAP greater than CAO and CAP greater than CAU greater than CAO greater than CAM for the OT and AVP binding sites, respectively. The displacement of oxytocin and arginine-vasopressin, respectively, from the myometrial receptor sites indicate partly separate binding sites for oxytocin and AVP and might implicate that AVP can be of importance in regulating myometrial activity in pregnancy. The results on oxytocin analogues imply that other pharmacological tests must be performed for quantification of the relaxing effects on the uterus and to determine the optimal analogue for clinical trials in preterm labor and dysmenorrhoea.
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PMID:Binding of four oxytocin analogues to myometrial oxytocin and arginine-vasopressin binding sites in pregnant women. 216 84

Nanosecond time-resolved tyrosinate fluorescence lifetimes were compared for oxytocin (OXT) and vasopressin (AVP) in propylene glycol. Long-lifetime tyrosinate fluorescence (LTF), characteristic of stable intramolecular hydrogen bond formation of the Tyr hydroxyl group, was present for OXT but not AVP in propylene glycol. The Tyr OH proton was also found to be labile for OXT but not AVP in DMSO by 1H-NMR. The spectroscopic data illustrate that the Tyr hydroxyl in OXT participates in an intramolecular hydrogen bond in certain receptor-simulating environments; the absence of potent LTF for [Ala5] OXT suggests that the Tyr hydroxyl of OXT forms an H-bond with the Asn5 carboxamide side-chain. The lability of the Tyr OH proton of OXT, but not AVP, is in accord with the biological activities of the peptides (OXT 100%, AVP 1%) in the rat uterus assay, suggesting that propylene glycol and DMSO mimic the environment at uterine receptors. 1H-NMR studies in DMSO demonstrate that for AVP there is a perpendicular-plate ring pairing interaction between the Tyr and Phe side-chains in which the hexagonal axis of the Tyr ring interacts with the face of the Phe ring. The present findings are discussed in terms of the proposed "cooperative model" for neurohypophysial hormone action.
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PMID:Tyrosinate fluorescence lifetimes for oxytocin and vasopressin in receptor-simulating environments: relationship to biological activity and 1H-NMR data. 217 14

Tissue specimens from the fundus, isthmus and distal cervix were obtained from 14 women at hysterectomy at various phases of the menstrual cycle. Ring preparations of small intramyometrial and intracervical arteries were dissected and mounted in organ baths; isometric tension was recorded and responses to contractile agents were studied. The amplitude of responses to K+ (124 mmol/l) of the vessel preparations ranked fundus greater than or equal to isthmus greater than cervix. While similar pD2 values for noradrenaline (NA) were found, the Emax values ranked cervix greater than or equal to isthmus greater than or equal to fundus (cervix greater than fundus). The pD2 values for arginine-vasopressin (AVP) showed minor differences, while the Emax values for this peptide ranked fundus greater than or equal to isthmus greater than or equal to cervix (fundus greater than cervix). Arteries from the fundus and isthmus displayed weak, inconsistent contractile responses to prostaglandin F2 alpha, but more pronounced contractions were induced by this prostanoid in arterial preparations from the distal cervix. The results suggest regional differences in vascular mechanical responses to endogenous vasoactive agents in the human uterus.
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PMID:Regional differences in vascular responses in the human uterus. 225 69

Recent reports have presented evidence suggesting that there are distinct oxytocin (OT) and vasopressin (VP) receptors in the human and rabbit myometrium. In this study we have investigated whether OT and arginine vasopressin (AVP) activate the same or two different receptor systems in the rat uterus in producing their uterotonic action and whether the myometrial OT/VP receptors are similar to the V1 receptors in the vascular smooth muscle cells. We compared the dose-response characteristics of OT and AVP by the in vitro cumulative dose-response curve technique. We determined the ligand-receptor binding characteristics of [3H]OT and [3H]AVP on uterine membrane fractions from nonpregnant and pregnant rats. Specific OT antagonists were used in competition receptor binding assays and in antioxytocic pA2 bioassays against OT and AVP to determine whether OT antagonists can discriminate between OT- and AVP-binding sites in the myometrium. We also compared the in vitro antioxytocic (OT receptor-mediated action) and the in vivo antivasopressor (V1 receptor-mediated action) potencies of a series of six OT antagonists. Our results show that OT- and AVP-binding sites in the nonpregnant rat uterus have similar binding characteristics and cannot be distinguished by the dose-response study, radioligand receptor binding assays, or OT antagonists in the competition binding and pA2 assays. However, in the term pregnant parturient uterus, the two binding sites can be clearly differentiated. OT receptor density, but not AVP, was markedly increased at term pregnancy. All six OT antagonists studied in this investigation were more potent in antagonizing the uterotonic response to OT than the vasopressor response to AVP. The antioxytocic:antivasopressor potency ratios, however, were different between the antagonists, ranging from nearly equal (0.91) to low (0.1). The results above suggest that there are distinct OT- and AVP-binding sites in the rat myometrium. The myometrial OT/AVP receptors are similar to but not the same as the V1 receptors in the vascular smooth muscle cells.
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PMID:Oxytocin- and vasopressin-binding sites in the rat uterus: competition binding and inhibitory pA2 studies with oxytocin and oxytocin antagonists. 231 58

The hormone relaxin has recently been shown to inhibit not only uterine muscle contraction, but also the release of oxytocin into the plasma. Intravenous injection of porcine relaxin in anaesthetized lactating rats inhibits milk ejection and injection of relaxin into the cerebral ventricles disturbs the pattern of the milk ejection reflex. Recent experiments performed in vivo indicate that relaxin might act not only in the uterus, but also in the hypothalamus and possibly in the neurohypophysis. We tested this hypothesis in vitro by studying the effect of relaxin on hormone release from isolated neural lobes of the pituitary and isolated neurosecretory nerve endings of the neurohypophysis from the rat. We report here that relaxin has a dual effect on neurohypophysial hormone secretion. Under basal conditions, vasopressin and oxytocin release was inhibited by relaxin but, when the nerve endings were depolarized, vasopressin and oxytocin secretion was potentiated. We also found that relaxin acts at a stage before the increase in cytoplasmic free Ca2+ that is necessary for inducing hormone release, possibly by gating the calcium channel.
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PMID:Relaxin affects the release of oxytocin and vasopressin from the neurohypophysis. 243 61

The neuropeptides vasopressin and oxytocin were first characterized as hormones, i. e., signalling molecules which are synthesized in hypothalamic neurones, transported toward the neurohypophysis and from there secreted into the general circulation. Although extrahypophysial Gomori-positive pathways were described in the brain as early as the mid-1950s, it is only during the last decade that the neurotransmitter role of vasopressin and oxytocin has begun to be investigated. Recent electrophysiological and morphological studies from our laboratory are summarized. Using extracellular and intracellular recordings from in vitro brain slices, a direct excitatory action of vasopressin was demonstrated in the lateral septum and in the nucleus of the solitary tract. This action of vasopressin was mediated by V1-type receptors. An excitatory effect of oxytocin, mediated by receptors similar to those present in uterus, has also been found in the dorsal motor nucleus of the vagus nerve. In accordance with these results, light microscopic autoradiography showed the presence in these brain areas of high affinity binding sites for vasopressin and for oxytocin, respectively. While these data corroborate the notion that vasopressin and oxytocin are probably involved in interneuronal communications, several questions, however, remain. The membrane mechanism by which vasopressin and oxytocin cause neuronal excitation is still unknown and evidence that endogenous vasopressin and oxytocin act at central synapses deserves further investigation.
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PMID:Neurohypophysial hormones: neuronal effects in autonomic and limbic areas of the rat brain. 251 Jul 77

The purpose of the present study was to examine the tissue selectivity of several [Arg1-D-Phe7]-substituted analogs of bradykinin. Unlike D-Arg-[Hyp3-D-Phe7]-bradykinin (NPC567), which antagonizes bradykinin-induced contractions both in rat isolated uterus and guinea pig ileum, [D-Nal1-Thi5,8-D-Phe7]-bradykinin (NPC573) was active only in uterine smooth muscle. Binding studies revealed that, unlike several [D-Phe7]-substituted analogs, including NPC567, NPC573 competed with radiolabeled bradykinin neither at receptors in uterus nor ileum. Moreover, no [Arg1-D-Phe7]-substituted analog competed with bradykinin binding in guinea pig ileum, suggesting that these agents, which inhibit uterine but not ileal contractions to bradykinin, may not be bradykinin receptor antagonists. NPC573 inhibited [Arg8]-vasopressin-induced contraction of the uterus more potently than it did bradykinin, although NPC573 (and other [Arg1-D-Phe7]-substituted analogs tested) did not inhibit binding of a vasopressin antagonist either in uterus or liver membranes. We therefore suggest that [Arg1-D-Phe7]-substituted analogs of bradykinin inhibit contractions of uterine smooth muscle by a mechanism other than receptor antagonism. In addition, the tissue selectivity of these agents suggests that the mechanisms underlying bradykinin's contractile effect in uterus are different than in intestinal smooth muscle.
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PMID:[Arg1-D-Phe7]-substituted bradykinin analogs inhibit bradykinin- and vasopressin-induced contractions of uterine smooth muscle. 253 8


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