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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The affinity of vascular vasopressin receptors was studied to determine its role in altered vascular contractile sensitivity in deoxycorticosterone acetate (DOCA)-salt hypertension. Ring segments of rat mesenteric arteries were used to study vascular vasopressin receptors. Male Wistar rats were given subcutaneous injections of DOCA and 1% NaCl in the drinking water. Mesenteric arteries from hypertensive rats had a reduced contractile sensitivity to arginine vasopressin (AVP) and lysine vasopressin (LVP). The order of potency of vasopressin receptor agonists (AVP greater than LVP greater than oxytocin) was the same in arteries from hypertensive compared with normotensive animals. The affinity of the vasopressin receptor antagonist [deamino-Pen1,O-Me-Tyr2,Arg8] vasopressin, and the affinities of the vasopressin receptor agonists AVP and LVP were not altered during developing DOCA-salt hypertension. There was no change in contractile sensitivity to norepinephrine and KCl in arteries from hypertensive rats. The reduced vasopressin contractile sensitivity is not due to a change in vasopressin receptor affinity but may be a compensatory response to elevated blood pressure. These data suggest that increased vascular sensitivity does not contribute to elevated blood pressure during the developing stage of DOCA-salt hypertension.
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PMID:Reduced contractile sensitivity and vasopressin receptor affinity in DOCA-salt hypertension. 153 57

Wistar rats were selectively bred over 10 generations for differences in performance in a footshock-motivated brightness discrimination (BD) test in a Y-maze. High behavioral performance (Wis/HBP) and low behavioral performance (Wis/LBP) rat lines were obtained which differ significantly in all behavioral components tested: frequency of correct responses, number of trials to criterion, response latency (HBP less than LBP), and frequency of freezing behavior (HBP less than LBP), the latter suggesting differences in emotionality. In Wis/LBP rats, furthermore, the normal increase in behavioral performance between the training and the relearning session, which indicates the formation of a memory trace, disappeared during selection. In male breeders sampled during selection of the two lines (Wis/HBP: n = 17; Wis/LBP: n = 21), both arginine vasopressin (AVP) and oxytocin (OXT) contents were measured by radioimmunoassay in the motor cortex, septum/striatum, hippocampus, hypothalamus, medulla oblongata and posterior pituitary. Compared with the Wis/HBP rats, the Wis/LBP rats contained less AVP in the hippocampus (3.1 +/- 0.58 vs 8.3 +/- 1.4 pg/mg wet wt., mean +/- S.E.M., P less than 0.001), but more AVP in the medulla (1.7 +/- 0.20 vs 1.1 +/- 0.18 pg/mg, P less than 0.05). In contrast, no significant differences between the lines were detected with respect to OXT concentrations. In the Wis/LBP rats, moreover, the hippocampal AVP content decreased during selection (r = -0.645, P less than 0.01), while the acquisition response latency increased (r = 0.549, P less than 0.01). As a consequence, a significant, albeit weak, negative correlation (r = -0.483, P less than 0.05) was observed between the individual hippocampal AVP content and the response latency during acquisition. Thus, the results confirm the view that genetically determined differences in the hippocampal content of endogenous AVP may contribute to an individual's level of emotionality and behavioral performance.
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PMID:Vasopressin and oxytocin in brain areas of rats selectively bred for differences in behavioral performance. 161 70

A 23-year-old woman with Marfan's syndrome was scheduled for Cesarean section at 31 week gestation because of progressive aortic dissection. Since she had undergone two surgical corrections for scoliosis (Harrington rod instrumentation) 5 and 12 years ago, we selected general anesthesia. She had been taking diltiazem and propranolol for hypertension and tachycardia. Anesthesia was induced with thiopental 75 mg iv followed by O2-N2O-enflurane (4%) by face mask. Following iv administration of vecuronium 4 mg and tracheal injection of 4% lidocaine 120 mg, the trachea was intubated without a significant hemodynamic change. Anesthesia was maintained with O2-N2O-enflurane (0.5-1.5%) before delivery. Following delivery, enflurane was discontinued and small doses of fentanyl iv (total 0.2 mg) were given with iv infusion of nitroglycerin (0.2-0.5 micrograms.kg-1.min-1) during surgery. Bleeding after delivery was controllable by iv infusion of oxytocin. The Apgar score was good (9 at 1 min and 10 at 5 min respectively). Post-operative course was uneventful. Therapeutic abortion or Cesarean section should be performed as soon as possible in a patient with dissecting aortic aneurysm because of increasing risk of aneurysm rupture during pregnancy. During the surgery, minimal hemodynamic changes are required to prevent the rupture.
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PMID:[General anesthesia for cesarean section in a patient with Marfan's syndrome associated with dissecting aortic aneurysm]. 205 91

If we consider the chemical messengers in the central nervous system, there are about ten classic transmitters--the catecholamines, biogenic amines and amino acids--as opposed to over 50 different neuropeptides. These include previously well-established circulating hormones such as angiotensin, atrial natriuretic peptide, vasopressin and oxytocin, calcitonin and calcitonin gene related peptide (CGRP), the opioid family of peptides, gastrointestinal peptides, pituitary peptides and their releasing factors, and miscellaneous peptides such as the kinins, bombesin, gallanin, and others; all occur as neuropeptides in the brain. There is evidence supporting a role in central cardiovascular control for angiotensin, opioid peptides, substance P, neuropeptide Y, vasopressin, atrial natriuretic peptide, kinins, corticotropin releasing factor, bombesin, somatostatin, and some other peptides. They have been localized in brain areas known to be important for blood pressure regulation, and specific high-affinity peptide receptors have also been discovered. Upon central administration, these peptides produce cardiovascular effects, partly by interacting with other blood pressure-controlling neuroregulators, e.g. catecholamines and GABA. Central inhibition of brain peptide synthesis or interaction with competitive antagonists at the receptor site results in marked cardiovascular effects. Altered peptide levels and activity of synthesizing enzymes, as well as supersensitivity to the pressor action of some brain peptides, have been described in experimental models of hypertension. We are using angiotensin as a model peptide to study the peptidergic control of cardiovascular function.
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PMID:Peptidergic control of cardiovascular function: the angiotensin paradigm. 219 11

The effect of severity of hypertension on fetal heart rate tracing changes and neonatal outcomes was evaluated on all patients with hypertension seen in 1980 and 1981 (666 cases, 10% of the pregnant population) in the Chicago-Lying In Hospital. The patients were grouped according to severity of hypertension, and the fetal heart rate monitoring, drugs administered, mode of delivery, and neonatal outcome were analyzed. Half of the patients (326) had mild hypertension and 13% (87) had severe hypertension; the remainder (253) had moderate hypertension. There were 49% primiparous and 51% multiparous women. The diagnosis of preeclampsia was made in 76% of cases, and chronic hypertension in 19%. Only 12% of the total were premature by dates, but 47% of this group were among the severe group. Oxytocin was given to 50%, whereas delivery was spontaneous in 56% of cases, and by cesarean section in 22%. This was higher among the severe hypertension group (37%), and the prematurity rate was 47%. Nonstress testing was done in one third of cases and only nonreactivity was associated with neonatal death. Neonatal depression (Apgar score less than 6 at 5 minutes) was significantly associated with intrapartum fixed baseline and late decelerations; these were the best predictors of fetal outcome. The administration of magnesium sulfate, hydralazine, meperidine, or morphine did not predictably affect the fetal heart rate pattern. The perinatal mortality was 21% in the mild group and 36% and 138%, respectively, among moderate and severe cases of hypertension. Close antepartum and intrapartum surveillance, including proper fetal monitoring, should help to reduce risks for mother and fetus through timely intervention.
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PMID:Effects of hypertension on pregnancy monitoring and results. 222 Sep 23

The authors induced 105 deliveries by extraamniotic administration of PGE2 (prostin Upjohn). The initial dose was 1-2 tablets, depending on the maturity of the portio uteri. If the contractions did not start within two hours, the dose was repeated. The sac was disrupted when the contractions were regular and the os uteri was larger than 2 cm. If necessary uterine activity was stimulated by small doses of Oxytocin (in 29%). Indication for induction was a programmed delivery (44.7%), protraced pregnancy (31.5%), diabetes mellitus (10.5%), a period of more than 24 hours after drainage of amniotic fluid without contractions (5.7%), hypertension or renal disease during gestation (4.8%) and hypotrophy of the foetus (2.8%). Inductions were successful in 96.2% of the patients. The parity of the patients influenced the interval between the onset of induction and the onset of uterine contractions, the duration of the first and second stage of labour and the consumption of Prostin tablets. The age of the patient, occupation, obesity and operation on the uterus did not affect the success of induction. There were no serious pathological findings during the third stage of labour, nor serious side-effects. The condition of the neonates was satisfactory.
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PMID:[Labor induction using extra-amniotic administration of PGE2]. 235 Jul 87

The effect of using either normal saline or 5% glucose solution, as fluid vehicle for oxytocin, on postpartum blood pressure was investigated in 138 parturient women. Blood pressure measurements were done at the commencement of infusion, immediately after delivery, at 1 hour and at 12 hours postpartum. There was no significant difference in the mean values of the mean arterial pressures or in the frequency of occurrence of postpartum hypertension between the two groups.
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PMID:Choice of intravenous fluid infusion in labour and maternal postpartum blood pressure. 259

Prostaglandin E2 gel is a useful agent for ripening and dilating the cervix. Since it is not available in the US, it must be prepared by thawing and grinding a 20 mg prostaglandin E2 suppository, mixing in a small amount of methylcelulose gel, and blending. The resulting gel is stored frozen in a 3 ml plastic syringe. The gel may be administered intracervically, intravaginally, or extraamniotically. Cervical administration of .5 mg prostaglandin E2 in 2-3 ml of viscous gel is most popular, but intravaginal administration is easiest, although it requires a higher dose (1-5 mg prostaglandin E2 in 2-10 ml of gel). The condition of the cervix is usually favorable for labor induction within 12 hours (range 4-24 hours). 59 clinical trials were conducted among 3313 pregnancies. In patients with unfavorable cervix induction of labor was successful in 83% of those treated with the gel but in only 53% of untreated patients. In women with an unfavorable cervix the gel is more effective if administered intracervically. In patients with favorable cervix, 66% of nulliparas and 82% of multiparas were delivered without oxytocin. Prostaglandin E2 gel has been used successfully even in women with prolonged pregnancy, hypertension, ruptured membranes, and fetal death. It can also be used to induce late 1st trimester abortion. Side effects of the gel are mild and minor. Prostaglandin E2 gel has thus been shown to effect cervical ripening and dilatation, reduce induction failures, shorten the induction-delivery interval, reduce oxytocin use, and lower the need for cesarean sections. Prefabricated prostaglandin E2 delivery systems should be approved by the Food and Drug Administration for commercial use.
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PMID:Prostaglandin E2 gel for cervical ripening and induction of labor: a critical analysis. 264 30

The objective of these studies was to investigate the role of arterial baroreceptors in the control of neurohypophyseal secretion. The effect of sinoaortic denervation on basal and osmotic-induced release of oxytocin and vasopressin and on blood pressure was determined. Hypertonic or isotonic saline was infused intravenously into sham-operated or denervated rats 3 days after surgery. Plasma oxytocin and vasopressin were measured at 5 and 15 minutes after the infusion. The control levels of oxytocin were increased in the denervated rats, but vasopressin levels were not significantly altered. The vasopressin and oxytocin responses to hypertonic saline were greater after baroreceptor denervation. Plasma oxytocin was increased from 4.7 +/- 0.9 to 72.2 +/- 8.7 pg/ml in the denervated rats and from 1.8 +/- 0.3 to 39.9 +/- 6.7 pg/ml in the sham-operated control group at 5 minutes after the infusion (p less than 0.01). The plasma vasopressin response to hypertonic saline was 7.1 +/- 0.6 pg/ml in the sham-operated versus 11.1 +/- 1.6 pg/ml in the denervated rats (p less than 0.05). There was no difference between sham-operated and denervated rats in the effect of hypertonic saline on plasma sodium and hematocrit. Mean arterial blood pressure was increased after sinoaortic denervation (116.3 +/- 4.2 mm Hg in the sham-operated vs. 138.2 +/- 8.3 mm Hg in the denervated rats, p less than 0.05); however, there was no difference in the pressor response to hypertonic saline. These results show that the baroreceptor system influences the secretion of both oxytocin and vasopressin, with effects on basal secretion as well as the response to an osmotic stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1989 Feb
PMID:Baroreceptor influences on oxytocin and vasopressin secretion. 291 33

In vivo extracellular recordings from rat supraoptic and paraventricular magnocellular neurosecretory cells (MNCs) indicate that putative vasopressin-secreting MNCs may be identified by an abrupt and brief cessation in firing consequent to a transient drug-induced rise in arterial pressure sufficient to activate arterial baroreceptors. In the diagonal band of Broca (DBB), a population of neurons projecting towards the supraoptic nucleus are activated during this drug-induced hypertension. Electrical stimulation in DBB selectively depresses supraoptic vasopressin-secreting MNCs. Intracellular recordings in perfused hypothalamic explants confirm a DBB-evoked bicuculline-sensitive and chloride-dependent postsynaptic inhibition, similar to that associated with the application of gamma-aminobutyric acid (GABA) in approximately half of supraoptic MNCs. Since bicuculline also selectively blocks baroreceptor-induced inhibition in supraoptic MNCs, it is proposed that the depressant baroreflex input to vasopressin-secreting MNCs involves a population of DBB neurons and GABAergic interneurons located close to MNCs. An excitatory and selective input to vasopressin-secreting MNCs follows chemoreceptor activation, possibly mediated by the A1 noradrenergic cell group in the ventrolateral medulla. Another excitatory input to both vasopressin- and oxytocin-secreting MNCs is triggered by circulating angiotensin II and appears to be relayed centrally through an angiotensinergic projection from the subfornical organ.
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PMID:Cardiovascular input to hypothalamic neurosecretory neurons. 304 23


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