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

Turnover of noradrenaline (NA) and dopamine (DA) in some regions of the rat brain was determined after 1 and 3 weeks of daily injections of lysine vasopressin (LVP) and 2 weeks after the termination of 28-day LVP injections. Disappearance of 3H-DA was estimated in the hemispheres, brain stem and striatum and of 3H-NA in the hemispheres and brain stem after intraventricular injection of 3H-tyrosine. A significant acceleration of 3H-NA disappearance from the hemispheres was found in all the experimental animals and from the brain stem 3 weeks after LVP adminstration and 2 weeks after its withdrawal. No marked changes in dopamine turnover in the examined regions of the rat brain were found. Since prolonged vasopressin administration produces hypertension in the rat it seems likely that central NA, but not DA, plays a role in the vasopressin-induced hypertension.
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PMID:Turnover of catecholamines in some regions of the rat brain during prolonged vasopressin administration and after its withdrawal. 94 87

Clinical states with portal venous hypertension are frequently associated with impairment in renal hemodynamics and water excretion, as well as increased renin secretion. In the present investigation, portal venous pressure (PVP) was increased in anesthetized dogs undergoing a water diuresis. Renal arterial pressure was maintained constant in all studies. As PVP was increased from 6 to 20 mm Hg, decreases in cardiac output (2.5-2.0 liter/min, P less than 0.05) and mean arterial pressure (140-131 mm Hg, P less than 0.05) were observed. Increases in PVP were also associated with decreases in glomerular filtration rate (GFR, 40-31 ml/min, P less than 0.001), renal blood flow (RBF, 276-193 ml/min, P less than 0.001), and increases in renin secretion (232-939 U/min, P less than 0.025) in innervated kidneys. No significant change in either GFR or RBF and a decrease in renin secretion occurred with increases in PVP in denervated kidneys. To dissociate the changes in cardiac output and mean arterial pressure induced by increase PVP from the observed decreases in GFR and RBF, studies were performed on animals undergoing constriction of the thoracic inferior vena cava. In these studies, similar decreases in cardiac output and mean arterial pressure were not associated with significant changes in GFR or RBF. Increases in PVP also were associated with an antidiuresis as urine osmolality increased from 101 to 446 mosmol/kg H2O (P less than 0.001). This antidiuresis was significantly blunted but not abolished by acute hypophysectomy. In hypophysectomized animals, changes in free water clearance and urine flow were linearly correlated as PVP was increased. These studies indicate that increases in PVP result in decreases in GFR and RBF and increases in renin secretion mediated by increased renal adrenergic tone. Increased PVP is also associated with antidiuresis; this antidiuresis is mediated both by vasopressin release and by diminished tubular fluid delivery to the distal nephron.
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PMID:Mechanisms of portal hypertension-induced alterations in renal hemodynamics, renal water excretion, and renin secretion. 96 99

Twenty-six patients with the syndrome of inappropriate secretion of antidiuretic hormone were reviewed. The underlying diseases were bronchogenic carcinoma (12 cases); myxoedema (five cases); diseases of the nervous system (five cases); bronchopneumonia, carcinoma of the oesophagus, acute intermittent porphria and chlorpropamide therapy (each one case). Serum sodium levels ranged between 104 and 125 mEq per litre. Eighteen patients presented neurological manifestations, which in 14 were considered to be due to hyponatraemia. Neurological signs included disorders of consciousness (stage I and II coma), extrapyramidal signs, asterixis and epileptic seizures. An hyponatraemic coma was the first manifestation of the syndrome in five cases. In all cases where the EEG was recorded it showed non-specific signs of metabolic coma. The fundi never showed signs of intracranial hypertension. Blood urea and creatinine levels were invariably low in the euthyroid patients; these values were normal or elevated in patients with myxoedema and hyponatraemia. Hypokalaemia was frequent, and hypocalcaemia constant. In eleven cases an excess of water intake revealed the clinical syndrome: six patients were excessive beer drinkers and five had received extensive intravenous infusions. In one case the deleterious effect of diuretics was evident, and in another, the syndrome became evident during radiotherapy of an oesophageal tumour. Treatment of the syndrome was successful in all cases. A review of the literature concerning the various pathogenic mechanisms corresponding to the different underlying diseases is presented. The concept of aberrant hormonal production by a tumour is illustrated by an electron microscopic study.
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PMID:Clinical, biological and pathogenic features of the syndrome of inappropriate secretion of antidiuretic hormone. A review of 26 cases with marked hyponatraemia. 100 53

Maintenance of normotension rests upon the overall salt and water balance, which, in the event of disequilibrium, modifies body fluid, cardiac output and total peripheral resistance. The kidneys play a central role in this hydro-saline regulation. The central and autonomous nervous systems, the renin-angiotensin system, the mineralocorticoids, the antidiuretic hormone and the kallikrein-bradykinin-prostaglandin system all affect this regulation and are closely interrelated. The role of each of these nervous and endocrine systems in hypertension, and their close interrelationship, is briefly reviewed.
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PMID:[Physiopathology of arterial hypertension. Role of the nervous system and of the hormones]. 101

Involvement of the area postrema in experimental hypertension has been investigated. Ablation of the rear apex of the fourth brain ventricle (=the region of the area postrema) elevated blood pressure, heart rate and plasma angiotensin II level. The same characteristic changes were seen in the two kidney Goldblatt rat model of hypertension. A possible involvement of the area postrema in this model of hypertension is discussed. Intraventricular perfusion of angiotensin II elevated blood pressure without a significant change in heart rates. This pressor response appeared to be dependent on release of antidiuretic hormone. The results are discussed in relation to the intrinsic brain angiotensinogenase system.
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PMID:Central pressor actions of angiotensin II. 103 May 65

1. The role of arginine-vasopressin in the pathogenesis of malignant deoxycorticosterone (DOC) hypertension of rats was investigated. 2. In rats with malignant DOC hypertension plasma arginine-vasopressin concentrations increased more than tenfold subsequent to volume depletion and a rise of serum osmolality. 3. The injection of a specific antibody serum for arginine-vasopressin caused a marked fall of blood pressure in rats with malignant DOC hypertension, whereas the injection of angiotensin II antiserum did not affect blood pressure. 4. In rats exhibiting a benign course of DOC hypertension plasma concentrations of arginine-vasopressin were increased threefold in comparison with normotensive control rats; the injection of an arginine-vasopressin antiserum induced a significant but small fall of blood pressure. 5. It is concluded that in the pathogenesis of malignant DOC hypertension arginine-vasopressin might play the role that the renin-angiotensin system plays in the pathogenesis of malignant renal hypertension.
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PMID:Vasopressin and malignant deoxycorticosterone hypertension in rats. 107 63

1. The rate of renal excretion of arginine-vasopressin was determined during unrestricted fluid intake for 24 h and in response to fluid deprivation for 18 h in nine young men with very mild essential hypertension and compared with that in sixteen normotensive men of similar age. 2. Despite an equivalent osmolar stimulus, excretion of arginine-vasopressin was significantly greater in the reference group than in the reference group. This difference increased progressively with increasing dehydration. 3. We suggest that these findings are mainly due to an increased rate of secretion of arginine-vasopressin in response to mild hydropenia in hypertensive patients and that a moderate increase of release of arginine-vasopressin during periods of fluid deprivation may exert vascular effects and thus influence the perpetuation of hypertension.
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PMID:Increased renal excretion of arginine-vasopressin during mild hydropenia in young men with mild essential benign hypertension. 107 11

Five patients with an unusual encephalopathy, possible secondary to measles virus infection, are described. Features common to these patients are: an existing chronic disease, neurologic deterioration 2 1/2 to 6 months after a measles infection, and death several weeks later. These events occurred when the chronic disease (e.g. leukemia or neuroblastoma) was in remission. That the measles virus was the causative agent is suggested only by finding in brain and extracranial tissues intracytoplasmic and intranuclear inclusions which contained measleslike particles. Additional clinical features seen in each of the five patients were: seizures, hypertension, and the inappropriate secretion of antidiuretic hormone.
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PMID:Encephalopathy following measles infection in children with chronic illness. 127 Nov 91

With aging the content of the blood vasopressin increases. In old animals smaller doses of vasopressin induce coronary insufficiency (rise of T wave, shift of S-T segment, disorders of the atrio-ventricular conductivity). On continuous administration of vasopressin (during a month), arterial hypertension appears only in old animals due to increase in cardiac output, stroke volume at unchanged cardiac rhythm, and to some decrease in the total peripheral resistance.
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PMID:[Vasopressin concentration in the blood and sensitivity of the cardiovascular system to it during aging]. 127 35

Low doses of apomorphine (20-50 micrograms/kg) induced an increase in the activity of an endogenous inhibitor of cAMP dependent protein Kinases (type I inhibitor) in the striatum, anterior and posterior hypothalamus of normotensive rats by stimulating D2-dopamine receptors. In contrast, high doses of the compound (2-10 mg/kg) produced a dose dependent decrease in type I inhibitor activity. In the posterior hypothalamus of vasopressin hypertensive rats and SHR the maximal increase of type I inhibitor activity was markedly higher than in normotensive animals. Moreover, apomorphine induced the increase of type I inhibitor activity in a much wider range of doses. Only as high dose of the compound as 10 mg/kg was able to decrease type I inhibitor activity. This points to a marked supersensitivity of D2 receptors and suggests the subsensitivity of D1 receptors in this brain area of hypertensive rats. In contrast, in the striatum and anterior hypothalamus of hypertensive rats the apomorphine dose response curves were similar to those in normotensive rats. Thus, it seems tha hypertension is associated with the alteration in sensitivity of D2 and D1 receptors in the posterior hypothalamus, the brain area involved in regulation of blood pressure.
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PMID:The responsiveness of D1- and D2-dopamine receptors in the striatum and hypothalamus of spontaneous and vasopressin hypertensive rats. 128 99


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