Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The experiments were performed on male rats, drinking 2% NaCl solution ad libitum for 12 days instead of tap water. The pituitary gland was exposed by the transpharyngeal approach under urethane-chloralose anaesthesia. The posterior lobe remained in neural and partial vascular connection with the hypothalamus, whereas the anterior lobe was entirely removed. Samples of the outflow medium from the incubated in situ rat posterior pituitary lobe were collected during 30 min intervals. Substance P-like peptides and vasopressin activities were assayed by the biological tests. Injections of hypertonic solution into the internal carotid artery did not change vasopressin release, but induced an increase in Substance P release from the posterior pituitary lobe into the incubation medium. Under conditions of unexcitability of the osmosensitive cells, triggering vasopressin release, the injection of hypertonic solution into the internal carotid artery stimulated the Substance P-like peptides release from the posterior pituitary lobe.
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PMID:Substance P-like peptides and vasopressin release from posterior pituitary lobe incubated in situ after intracarotid injections of hypertonic solution in rats. 2 85

In pentobarbital (35.0 mg/kg) anaesthetised dogs, bolus injections of prazosin into the femoral artery (3.0--300.0 microgram) provoked a dose-related fall in the vascular resistance of the innervated hind limb. In contrast to papaverine, prazosin failed to produce the same effect in dogs under spinal anaesthesia even when the intrinsic femoral vascular tone was increased with vasopressin. However, vasodilator effects of prazosin were again observed when the tone of the limb was elevated by either stimulating the sympathetic lumbar chain or by infusing alpha-adrenoceptor agonists. A significant reduction of both aortic blood pressure and pressor response to bilateral carotid artery occlusion was noted in a group of normotensive dogs anaesthetised 12 h after the last dose of prazosin given twice daily at 0.5 mg/kg, p.o., for 3 day period. This short-term treatment modified neither the resting heart rate nor the positive chronotropic effect induced by either intravenous noradrenaline or electrical stimulation of pre- and post-ganglionic nerve fibres of the right stellate ganglion. However, it prevented the larger increase in heart rate in response to bilateral carotid occlusion in placebo-treated dogs after section of the vagi. A decrease in baseline sympathetic tone of the perfused hind limb as well as vasoconstrictor effects produced by i.a. injections of several alpha-adrenoceptor agonists and electrical stimulation of the lumbar sympathetic chain was observed in prazosin-treated animals. The dose--pressor response profiles to these alpha-adrenoceptor stimulants after prazosin were not parallel to those obtained in the control group. The vasoconstrictor response to angiotensin II was not changed by prazosin. In rabbit aortic strips, prazosin (0.1--3.0 micrometer) produced competitive antagonism of the contractile responses induced by cirazoline, noradrenaline and phenylephrine. In contrast to papaverine, prazosin in concentrations up to 100.0 micrometer neither relaxed the aortic strips contracted by potassium ions nor modified the concentration-response curve to calcium ions. These studies indicate that blood pressure lowering effects of prazosin given acutely or for three days can be accounted for by a clear-cut functional impairment of vascular postsynaptic alpha-adrenoceptors. No evidence for a direct myorelaxant property of prazosin could be obtained in these studies.
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PMID:Studies on the mechanism of the vasodilator effects of prazosin in dogs and rabbits. 2 80

Clonidine s.c. (0.01-0.3 mg/kg), in unanesthetized rats, caused an initial rise (+20 mm Hg), followed by a continuous fall of BP and a dose-dependent natriuresis and diuresis for up to 2 h. Glomerular filtration rate (GFR) (CIn) increased during the first 20 min, while effective renal plasma flow (ERPF) (CPAH) remained normal. Subsequently, between 20 and 60 min after injection, ERPF (CPAH) decreased considerably while GFR had reverted to its normal value. In saline-infused rats clonidine diuresis was accompanied by an "inappropriate" positive free water clearance. Pentobarbital anesthesia suppressed the initial BP peak and the diuresis. Phenoxybenzamine (1 mg/kg i.v.) was antinatriuretic in saline diuresis; the effect of phenoxybenzamine + clonidine on diuresis and salt excretion represented the sum of the effects of both drugs, but phenoxybenzamine enhanced the clonidine-induced increase of GFR. Neither haloperidol (1 mg/kg i.v.) nor bulbocapnine (3 mg/kg i.v.) interfered with the renal effects of clonidine. Clonidine s.c. caused hyperglycemia and glucosuria which did not account for the natriuresis. Clonidine thus appears to increase the GFR and "filtration fraction" (FF) by a phenoxybenzamine-insensitive rise of glomerular ultrafiltration, to depress ERPF by alpha-adrenergic afferent vasoconstriction, to induce natriuresis by a tubular action not blocked by phenoxybenzamine and to exert an antivasopressin effect, either by depressing pituitary vasopressin secretion or the renal response to vasopressin.
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PMID:The renal effects of clonidine in unanesthetized rats. 4 24

Using micropuncture techniques, the author studied the effect of vasopressin on renal function in young rats at three stages of development -- in the middle of the weaning period (22 days), after weaning was over (30 days) and at the beginning of the sexual maturation period (42 days). In the presence of a hypotonic load, a small dose of vasopressin (12 muU/100 g b.w., i.v.) was most effective in the youngest age group, where it reduced the urine flow by 82% both by increasing water reabsorption and by reducing the GFR. In this group, vasopressin lowered the TF/P Na+ ratio and raised the TF/P K+ ratio in the initial part of the distal tubules of the superficial nephrons, but raised water absorption only beyond the initial part of the distal tubules. Vasopressin reduced the urine flow by 72% in 30-day-old rats by raising water reabsorption beyond the initial part of the distal tubules. The only ion to be affected was K+, whose concentration rose in the final urine. In 42-day-old rats the effect of vasopressin was manifested in only mild depression of the GFR. In this age group, as distinct from younger animals, anaesthesia and surgery evidently led to endogenous vasopressin release, so that the small dose of exogenous vasopressin did not significantly influence the test parameters. This is also underlined by the significant difference between the control urine flow of the 42-day-old and the younger rats.
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PMID:The effect of vasopressin on renal function in young rats a clearance and micropuncture study. 13 28

Obviously, the analysis of dynamic changes in the hypothalamic activity of corticotropin-releasing factor (CRF) is essential for understanding of the central regulatory mechanism of ACTH secretion. However, the significance of the changes in CRF activity will be extremely lessened if the effect of CRF per se be modified at the pituitary level. In fact, Yates et al. (1971) reported that the CRF effect was potentiated by the presence of vasopressin. Therefore, in this study we attempted first to determine if vasopressin does potentiate the CRF action. Next, we analyzed some aspects of CRF dynamics in the rat hypothalamus under prolonged stress. (1) Potentiation of CRF action by vasopressin. This possibility was examined by the following approaches: i) Adrenocortical responses to various mild stressors (exposure to sound, i.p. injection of saline solution, tail cut) were greater in dehydrated rats than in normal controls. ii) Similarly, the adrenocortical response to intravenous injection of stalk-median eminence extract (SME) through the tail vein under Nembutal anesthesia was larger in the dehydrated rat than in control. iii) Prior to SME administration, vasopressin in a subthreshold dose was injected intravenously to assay rats pretreated with chlorpromazine (CPZ)-morphine (M)-Nembutal (Nb). The adrenocortical response to SME, injected into the carotid artery 1 min later, was found significantly to increase due to prior administration of vasopressin. iv) However, no potentiating effect of vasopressin was observed when SME and vasopressin (4 mU) were placed stimultaneously into the anterior pituitary tissue by the intrapituitary injection technique. v) In addition, no potentiating effect was observed in vitro incubation experiments under varying incubation conditions. Thus, it was shown that vasopressin has some potentiating effect on the stress response in vivo, but the effect is not at the pituitary level. (II) Analysis of dynamic changes in hypothalamic CRF activity. CRF activity was estimated by the intrapituitary injection method of Hiroshige, the plasma ACTH and corticosterone levels being followed simultaneously. Plasma ACTH was determined by radioimmunoassay partly with RCC-RIA Kit, and partly with ACTH antisera (kindly supplied by Dr. W.F. Ganong) by the method of Berson and Yalow. i) In intact normal rats, the response pattern of hypothalamic CRF activity under etherlaparotomy stress was characteristically biphasic, i.e., composed of rapid and slow phases, while the plasma ACTH and corticosterone showed a sustained high level over a 2 hr of observation period.
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PMID:[Analysis of dynamics of corticotropin-releasing factor (CRF) activity in the rat hypothalamus under stress]. 18 25

In vivo experiments were performed in male Wistar rats to elucidate the probable relation between renal concentrating ability and medullary cyclic AMP content as influenced by changes of hydration and by administration of antidiuretic hormone (ADH). Cyclic AMP levels were 37% lower in water diuretic than in control animals (P less than 0.01), but were not significantly changed during prolonged antidiuresis induced by dehydration or ADH administration. Nor could any change of cyclic AMP levels be demonstrated between 2 and 20 min after ADH injection. Significant increases of medullary cyclic AMP content occurred following stress, anesthesia, and administration of isoproterenol and 3-isobutyl-1-methylxanthin. The results suggest that the level of cyclic AMP in the renal medulla may not be an important determinant of the antidiuretic response produced by ADH in rats.
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PMID:Dissociation between antidiuretic response and renal medullary cyclic AMP levels in the rat. 20 98

The effect of increased concentration of vasopressin and oxytocin in the cerebrospinal fluid on the excitability of the hypoglossal nerve nucleus was investigated. The experiments were carried out on rats under chloralose anaesthesia. Retractory jerks of the outstretched tongue were evoked by supra- or infraorbital nerve stimulation during perfusion of the cerebral ventricles with McIlwain-Rodnight solution. The solution contained synthetic arginine vasopressin 0.05 U/ml or synthetic oxytocin 0.05 U/ml. Perfusion of the ventricles with vasopressin increased and perfusion with oxytocin decreased the evoked tongue jerks.
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PMID:Effect of vasopressin and oxytocin perfusion of the cerebral ventricles on evoked tongue jerks. 21 38

Forty-five patients underwent enflurane anaesthesia and surgery. Anaesthesia alone evoked little change in the plasma concentrations of ACTH, cortisol or antidiuretic hormone (ADH), but there were significant increases during surgery. The plasma levels of aldosterone rose during anaesthesia alone, and a further increase was noted during surgery. Neither enflurane anaesthesia nor surgery significantly influenced plasma concentrations of renin activity and thyroxine. A significant decrease in the plasma triiodothyronine levels was detected during anaesthesia alone, and a further decrease was found during and following surgery. Enflurane anaesthesia did not affect the plasma level of luteinizing hormone (LH) in male subjects throughout surgery, but a significant decrease was detected in female patients on the first postoperative day. The plasma concentrations of testosterone decreased during anaesthesia alone and surgery, and a further decrease was noted on the first postoperative day.
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PMID:Effects of enflurane anaesthesia and surgery on endocrine function in man. 23 72

In acute gastrointestinal bleeding visceral angiography has been showing its importance for years. It contributes to diagnosis especially in cases with persistent acute hemorrhage. In chronic gastrointestinal bleeding conventional radiographic procedures such as upper gastrointestinal series and barium enema will be preferred to angiography. The function of the radiologist goes beyond mere diagnosis of gastrointestinal bleeding. Treatment with vasopressin via the angiographic catheter has proven its clinical value. This method will be indicated especially in cases with high risk anesthesia and surgery. It will help to postpone necessary surgery to a more favorable moment following hemostasis. Side effects such as hypertension and antidiuresis are relatively rare and easy to manage. Numerous substances are used for embolization showing that ideal material has not been found yet and further development seems necessary. In contrast to vasopressin treatment, vascular occlusion is often irreversible, complications (unwanted reflux of embolization material, necrosis and plugging of the catheter) are more difficult to manage. Superselective visualization of a bleeding artery is always needed. Embolization is justified in cases when a possibility for anesthesia and surgery cannot be foreseen. The electrical vascular occlusion using direct current is still in the phase of animal experiments; its clinical value has not sufficiently been assessed as yet.
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PMID:[Angiographic diagnosis and therapy of acute and chronic gastrointestinal hemorrhages]. 30 84

Plasma vasopressin concentrations were estimated in twelve patients undergoing cardio-pulmonary bypass for open heart surgery. In six patients anaesthesia was maintained with 66% nitrous oxide in oxygen, whilst the remaining six additionally received halothan as a vasodilator during the bypass period. Induction of anaesthesia had little effect on plasma vasopressin concentrations, whilst marked increases were seen during surgery and bypass in both groups of patients. However, in those patients receiving halothane, significantly higher concentrations were reached, a maximun b36.1 +/- 8.9 (SEM) muu/ml being seen in contrase to 15.4 +/- 2.2 muu/ml in the group receiving nitrous oxide in oxygen alone.
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PMID:The effects of halothane on plasma vasopressin during cardio-pulmonary bypass. 32 88


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