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)

The stimulatory effect of dopamine (DA) on the release of oxytocin (OT) in lactating rats is exerted at the D-1 DA receptor subtype. Because the neural loci mediating this effect have not been identified, the objective of the present studies was to test whether OT release in the lactating rat would be elevated after central administration of a D-1 DA receptor agonist into the third ventricle (3V) or directly into either the rostral paraventricular/anterior commissural nucleus area (PVN/ACN), the central paraventricular nucleus area, or the supraoptic nucleus (SON), all of which contain OT neurosecretory cells. Lactating rats were implanted with a stainless steel cannula directed into one of the above areas or into the arcuate-ventromedial region of the medial basal hypothalamus (MBH), or sites dorsal to the PVN/ACN or SON, which served as anatomical controls. After 6-7 days of recovery, each animal received an intra-atrial cannula for sequential blood sampling, and was used in experiments 24 h later. Animals were separated from their litters, and following a period of basal blood sampling, received central microinjections of either vehicle, the D-1 DA receptor agonist SKF-38393, or the D-2 DA receptor agonist quinpirole, and blood samples were removed periodically for 60 min. An injection of angiotensin II (Ang II, 100 ng) was made into each site as a positive control for OT release.(ABSTRACT TRUNCATED AT 250 WORDS)
Neuroendocrinology 1992 Sep
PMID:Activation of central D-1 dopamine receptors stimulates oxytocin release in the lactating rat: evidence for involvement of the hypothalamic paraventricular and supraoptic nuclei. 143 76

The firing rate and pattern of activity of neurons in the anterior commissural nucleus (ACN), which was rich in oxytocin-containing neurons, were studied electrophysiologically in hypothalamic slices. Extracellular recording showed that most ACN neurons exhibited irregular or regular continuous spontaneous unit activity. Other neurons showed short burst patterns of activity or were silent. The majority of ACN neurons were activated by bath application of angiotensin II, and a substantial number of them showed inhibitory or excitatory responses to hypertonic bathing medium. These results indicate that magnocellular neurosecretory neurons in the ACN may participate in the regulation of water balance.
Neurosci Lett 1992 Sep 14
PMID:Neuronal responses of the anterior commissural nucleus to osmotic stimulation and angiotensin II in hypothalamic slices in the rat. 143 19

We tested a new method of monitoring intrauterine contraction pressure. The pressure transducer is simply inserted between the fetal membranes and uterus after checking placental placement with ultrasonography. To evaluate this method, a prospective, randomized study was done to compare intraovular versus extraovular intrauterine contraction monitoring in patients undergoing serial labor induction with oxytocin. Study parameters were length of labor, cesarean section rate, Apgar scores and febrile morbidity rate. Two groups of 32 patients each underwent oxytocin induction for postdatism, diabetes or hypertensive disorders of pregnancy. Our results show that extraovular intrauterine contraction monitoring resulted in a better outcome with respect to all the parameters evaluated. Specifically, it had a shorter induction interval, lower cesarean section rate, lower rate of maternal febrile morbidity and comparable neonatal complications. The technique was safe and easy to learn and apply.
J Reprod Med 1992 Sep
PMID:Extraovular and intraovular uterine contraction monitoring. A comparison. 145 4

In 1989-90 in India, physicians used 4 different methods to induce second trimester abortion (14-20 weeks gestation) in 200 women at the Lokmanya Tilak Municipal General Hospital in Sion in Bombay. In 50 women each, they introduced 200 ml of 20% hypertonic saline into the amniotic sac, after removing 35-200 ml of amniotic fluid; 150 ml of ethacridine lactate extraovularly; prostaglandin F2 intramuscularly at regular intervals; and a cupful of 5% povidone-iodine topical solution in 150 ml of sterile normal saline extraamniotically. Intravenous oxytocin drip was started the morning after induction in all but those women receiving prostaglandin F2 to reduce the induction-abortion interval. 5% povidone-iodine solution successfully induced abortion in 100% of cases. The success rates for ethacridine lactate, hypertonic solution, and prostaglandin F2 were 98, 96 and 90%, respectively. Ethacridine lactate had the highest complete abortion rate (42%) followed closely by 5% povidone-iodine (39%). Prostaglandin F2 resulted in the shortest mean induction-abortion interval (20 hours vs. 38 hours for hypertonic solution, 30 hours for ethacridine lactate, and 32 hours for 5% povidone-iodine solution. 4 (8%) of the 50 women who underwent an abortion induced by hypertonic solution required a blood transfusion. Another woman undergoing hypertonic solution abortion developed disseminated intravascular coagulation and died. The only women who experienced vomiting and loose stools were women receiving prostaglandin F2 (30 women [60%]). The most cost-effective abortion method was 5% povidone-iodine solution in normal saline, indicating that this is the preferred method for poor patients.
J Indian Med Assoc 1992 Sep
PMID:Comparative study of midtrimester termination of pregnancy using hypertonic saline, ethacridine lactate, prostaglandin analogue and iodine-saline. 146 Mar 14

The nucleus of the solitary tract (NTS) is one of the brain regions by which arginine vasopressin (AVP) influences blood pressure. This series of experiments in adult male rats was designed to determine whether the AVP binding sites which have been demonstrated in the NTS by in vitro autoradiography might be presynaptic on vagal afferents from the nodose ganglion; whether the AVP binding sites on vagal afferent neurones are functional receptors; and whether vagal transport of AVP receptors to other organs also occurs. High affinity binding sites (using the selective V1 antagonist radioligand [125I][d(CH2)5,Sar7]AVP and in vitro autoradiography) with characteristics of V1 receptors in the medial subnucleus of the NTS were reduced by 40% ipsilateral to nodose ganglionectomy. The nodose ganglion itself also contained high affinity V1 AVP binding sites that localised over cell bodies of vagal sensory neurones. That these binding sites were functional receptors was apparent when low concentrations of AVP but not oxytocin were found to depolarize the isolated nodose ganglion utilizing the 'silicone grease gap' technique. Furthermore, the actions of AVP were antagonised by low concentrations of a selective V1 receptor antagonist. However, there was no accumulation of AVP binding sites adjacent to either the proximal or distal vagal ligations suggesting that peripheral vagal transport of AVP receptors may not occur. Therefore these results are consistent with functional AVP V1 receptors occurring in the nodose ganglion. These receptors may occur on central terminals of vagal sensory neurones in the medial subnucleus of the NTS, but there was no evidence for peripheral transport of AVP V1 receptors.
Neurosci Lett 1992 Sep 28
PMID:Presence of functional vasopressin V1 receptors in rat vagal afferent neurones. 146 73

In vivo experiments on the vasoactive effects of vasopressin and oxytocin on cerebral circulation were carried out in anesthetized dogs, using an electromagnetic flowmeter to measure vertebral blood flow and angiography to measure the internal diameter of the basilar artery. Direct bolus infusion of 1 pmol to 1 nmol of vasopressin or 10 pmol to 10 nmol of oxytocin into a femoral-vertebral artery shunt produced a dose-dependent decrease in vertebral artery blood flow without significantly affecting mean arterial blood pressure. Vasopressin was more potent than endothelin and neuropeptide Y, which have also been demonstrated to induce long-lasting decreases in vertebral artery blood flow. However, direct bolus infusion of vasopressin (100 pmol and 1 nmol) or oxytocin (1 nmol and 10 nmol) into the vertebral artery dilated major vessels including the vertebral, anterior spinal, and basilar arteries, as well as the circle of Willis and its main branches, while endothelin (1 nmol) and neuropeptide Y (5 nmol) caused no change in the diameters of major cerebral arteries. The V1 antagonist d(CH2)5tyrosine(methyl) arginine vasopressin suppressed the effects of both vasopressin and oxytocin. Vasopressin was over 10 times as potent as oxytocin in both assays. The vasodilatory effect of vasopressin, which may be mediated by an endothelium-dependent mechanism, was functionally damaged in dogs after experimental subarachnoid hemorrhage. These data suggest regional differences in the sensitivity and responsiveness of vasculature to vasopressin and oxytocin, and specifically that both peptides act through V1 receptors to decrease the resistance of large vessels and increase the resistance of small vessels.
J Neurosurg 1992 Sep
PMID:Effects of vasopressin and oxytocin on canine cerebral circulation in vivo. 150 90

Currently there is considerable interest in the actions of oxytocin antagonists on the pregnant myometrium. Few studies have been conducted involving long-term infusions of oxytocin antagonists to late-pregnant experimental animals. We set out to determine whether continuous infusion of an oxytocin antagonist ([1-beta-mercapto(beta-(CH2)5)1(OMe)Tyr2,Orn8]-oxytocin) would influence basal levels of myometrial activity of the contracture type and maternal prostaglandins in pregnant sheep. The antagonist was infused into a uterine vein at 80 micrograms.h-1 for 48 h starting at 139 days of gestational age. The antagonist significantly reduced total myometrial electromyogram activity and the frequency of contractures but did not change contracture duration. Antagonist infusion did not produce any significant alterations in maternal carotid or uterine vein 13,14-dihydro-15 keto prostaglandin F2 alpha concentrations. Contractures probably represent an intrinsic instability of the resting membrane potential of uterine muscle and these results suggest that oxytocin may play a role in regulating their frequency in sheep during the last third of gestation.
Biol Reprod 1992 Sep
PMID:Effect of 48-hour infusion of the synthetic oxytocin antagonist, [1-beta-mercapto(beta-(CH2)5)1(OMe)Tyr2,Orn8]-oxytocin, on myometrial activity of pregnant sheep at 139-140 days of gestation. 151 Oct 97

1. All women with PCS should be considered candidates for vaginal delivery. Certain high-risk factors then should be used to recommend elective repeat cesarean section. Currently, a scar in the active segment of the uterus is considered an absolute contraindication to labor. 2. Women should be informed of the chances of success (which in most instances are excellent), course of action in labor, and the rare risk of uterine rupture. 3. Women in a very low risk category (one low-transverse PCS) should be managed like any laboring patient but including fetal monitoring. 4. The remaining laboring patients may benefit from more intensive intrapartum surveillance, including continuous electronic fetal monitoring, early rupture of the fetal membranes, and placement of an intrauterine pressure catheter. 5. The labor course in women with PCS will depend on the number of vaginal deliveries achieved previously and the stage of labor reached before the cesarean section was done. 6. Labor disorders in patients with PCS, as in all patients, should be diagnosed and managed promptly. 7. Neither oxytocin nor epidural use is contraindicated in these patients. As in any patient, care should be taken to avoid iatrogenic uterine hyperstimulation. 8. Uterine rupture may have many different presentations. However, the most common is abnormal fetal heart rate patterns that are especially variable or prolonged decelerations. 9. Most uterine ruptures can be repaired and do not require hysterectomy. Hysterectomy may be the appropriate choice in some situations. 10. A history of a prior uterine rupture is not a contraindication to future childbearing, but it may place the woman at greater risk for a repeat event.
Clin Obstet Gynecol 1992 Sep
PMID:Labor after prior cesarean section. 152 74

Uterine activity may be defined in terms of the frequency of contractions of the uterus and the pressure generated by these contractions. Most studies that report an effect of analgesia on labor are retrospective, and, if prospective, are nonrandomized. Drug effects on uterine activity and labor progress are probably dose related, but are also influenced by a myriad of other factors including, but not limited to, the mother's emotional state, degree of cervical change, uterine contractility pattern, phase of labor, and individual differences in pharmacokinetics and drug sensitivity. The latest phase of labor may be prolonged by excessive narcotic or inappropriate timing of regional analgesia. The normal active phase tends to be resistant to the inhibitory effects of the usual amount of any analgesia. A brief period of decreased uterine activity often follows institution of analgesia. This may effectually accelerate labor in some patients by decreasing maternal anxiety and serum concentrations of catecholamines. A combination of sedation epidural blockade, and subsequent oxytocin use may prove effective in correcting a dysfunctional or hyperstimulatory pattern during the active phase. The second stage of labor may be slightly prolonged by effective epidural analgesia, but this delay is not necessarily harmful as long as the fetal heart rate tracing is normal, maternal hydration is adequate, and maternal pain relief is sufficient.
Clin Obstet Gynecol 1992 Sep
PMID:Effects of analgesia on labor. 152 75

Specific low-affinity high-capacity binding sites for gonadotropin-releasing hormone (GnRH) have recently been discovered in human breast and ovarian carcinomata. We checked whether similar binding sites are present in human endometrial cancer. Plasma membrane preparations were incubated with [125I,D-Ala6-desGly10]-GnRH-ethylamide in the presence or absence of unlabelled GnRH agonists or other peptides. GnRH-binding could be demonstrated in all 12 tumor samples tested. The mathematical analysis of the binding data was consistent with a single class of low affinity (Ka = (0.8-1.4) x 10(5) M-1) and high-capacity (Bmax = (134-142) x 10(-12) M/mg membrane protein) binding sites. Native GnRH had a similar affinity to the binding sites as the GnRH agonist used. Other peptides such as oxytocin, somatostatin and thyrotropin-releasing hormone did not crossreact with the binding sites. A photolabelled derivative of [D-Lys6]-GnRH was prepared with the bifunctional photolabile reagent (4-azidobenzyl)-N-hydroxysuccinimide. Photoaffinity labelling of endometrial carcinoma membranes and subsequent sodium dodecyl sulfate electrophoresis in 10% polyacrylamide gel revealed the presence of a single molecular mass component of 62 +/- 1.9 kDa. The appearance of this photolabelled binding site could be largely suppressed by the addition of unlabelled GnRH-agonist (10(-4) M) and thus represents the specific binding site for GnRH in endometrial cancer.
Eur J Obstet Gynecol Reprod Biol 1991 Sep 13
PMID:Specific low affinity binding sites for gonadotropin-releasing hormone in human endometrial carcinomata. 165 55


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