Development Of Renovascular Hypertension Research Articles

Effect of stenosis of the renal artery on the genesis and development of renovascular hypertension

Effect of stenosis of the renal artery on the genesis and development of renovascular hypertension

Indirect blood pressure determination by Doppler technique in renal hypertensive cats.

The Doppler ultrasonic recording technique was used to measure systolic and diastolic blood pressures indirectly in renal hypertensive cats. The accuracy of the method was evaluated by comparing indirect blood pressures from one leg of a cat with direct pressure measurements from the other leg. A linear relationship existed between indirect and direct systolic and diastolic pressures. The consistency of the method was assessed by measuring blood pressure during a 5-h monitoring period in normotensive and renal hypertensive cats. No significant variation occurred over this period. The sensitivity of the method to blood pressure changes was determined also. A significant reduction in systolic and diastolic pressure induced by hydralazine, 10 mg/kg po, was recorded during a 5-h monitoring period. The development of renovascular hypertension was followed for approximately 70 days. Systolic pressure rose in a logarithmic fashion from 160 to a maximum of 240 mmHg. It was concluded that the Doppler ultrasonic technique is a simple and reliable method for recording indirect blood pressure acutely and chronically in conscious unrestrained cats.

Catecholamine synthesizing enzymes in brain stem and hypothalamus during the development of renovascular hypertension

The activities of tyrosine hydroxylase (TH) and phenylethanolamine N-methyl-transferase (PNMT) have been measured in brain stem and hypothalamic nuclei during the development of renovascular hypertension. TH activity fell at 72 h in the posterior hypothalamic and peri- and paraventricular nuclei of the hypothalamus, but had returned to control levels by 7 days. PNMT activity was raised in the nucleus of the solitary tract at 7 days and was also elevated in the nucleus of the solitary tract, parahypoglossal nucleus, locus coeruleus and cerebellar cortex at 4 weeks. No change in PNMT was noted in hypothalamus. It appears from these results that both central noradrenergic and adrenergic pathways are involved in the development of this model of experimental hypertension.

Progression of medial fibroplasia of the renal artery and the development of renovascular hypertension.

A 33-year-old normotensive white women was rejected as a kidney donor because arteriography disclosed medial fibroplasia of the right renal artery. 44 months later she became hypertensive and arteriography revealed progression of the lesion. When renal venous renin assay demonstrated lateralization, a saphenous vein aortico-distal right renal arterial bypass graft was done; her blood pressure has been normal for more than 2 years since. Such patients should not donate kidneys because the course of renal arterial dysplastic lesions cannot be predicted.

Brain catecholamines and catecholamine-synthesizing enzymes in renovascular hypertension in the rat.

1. Noradrenaline content of several rat brain stem and hypothalamic nuclei falls transiently at 72 h after initiation of renovascular hypertension (one-kidney Goldblatt model). 2. Tyrosine hydroxylase activity is significantly reduced in posterior, paraventricular and periventricular nuclei of hypothalamus at this time but returns to control value by 7 days. 3. Treatment with hydrallazine, 5 mg/kg intraperitoneally, twice daily or methaoxamine, 5 mg/kg, three times daily for 3 days respectively raises and lowers the noradrenaline content of brain nuclei, suggesting that short-term changes in noradrenaline may be secondary to afferent baroreceptor input. 4. At later times after the development of renovascular hypertension (7 and 28 days) activity of phenylethanolamine-N-methyl transferase is increased in the nucleus of the solitary tract and the locus coeruleus. 5. Brain catecholamines may participate both early in the development and later in the maintenance of renovascular hypertension.

Changes in noradrenaline concentration in brain stem and hypothalamic nuclei during the development of renovascular hypertension

Changes in noradrenaline concentration in brain stem and hypothalamic nuclei during the development of renovascular hypertension

Effects of propranolol on the development of renovascular hypertension in the rat

To study the effects of beta-adrenergic blockade on the development of experimental renovascular hypertension, propranolol was administered subcutaneously to 20 male Sprague Dawley rats at a dose of 20 mg./Kg of body weight three times daily. The left renal artery was constricted after three days of treatment, leaving the right kidney untouched. The same procedure was performed in 20 controls which were given dextrose instead of propranolol. Treatment was continued in both groups for four weeks after constriction. At the end of the fourth week, only five (25 per cent) of the propranolol-treated rats developed hypertension (systolic pressure 160 mm. Hg or higher) as compared to 16 (80 per cent) in the control group ( p <0.001). The five rats that developed hypertension in the propranolol group had severe hypertension (BP≥190 mm. Hg) and high plasma renin activity. The average systolic pressure for the propranolol-treated group (hypertensive and normotensive) was 134±11, and 182±7 in the control group ( p <0.001). Heart rate was significantly lower in the propranolol group than in the controls (388±4 vs. 445±9 beats/min., p <0.001). Plasma renin activity was lower in the propranolol-treated rats than in the controls (4.0±1.2 and 8.2±1.6 ng./ml./hr., respectively, p <0.05). There was no difference in body weight between the two groups. Heart weight was lower in the propranolol-treated rats when compared with the controls (917±18 and 1012±30 mg., respectively, p <0.025). A third group of rats received propranolol after clipping, when renovascular hypertension had been well established. No significant decrease in blood pressure or peripheral renin activity was observed in this group, although heart rate was significantly decreased ( p <0.05). Our results indicate that established renovascular hypertension in rats is not affected by beta-adrenergic blockade. Propranolol, however, decreases the incidence of development of hypertension in rats when administered prior to, and for four weeks after renal artery constriction.

Kinetocardiographic study of contractions of the left and right ventricles during the development of renovascular hypertension in dogs of different ages

Kinetocardiograms of the left and right ventricles were recorded in puppies and adult dogs during development of experimental renovascular hypertension. The development of hypertension in adult dogs led to shortening of the expulsion period, but to its lengthening in puppies. Vector analysis of the kinetocardiograms showed that a syndrome of hypodynamia of the left ventricle, followed by a syndrome of high diastolic pressure, is observed in adult dogs; in puppies a phasic syndrome of high diastolic pressure, followed by a syndrome of stenosis of the outlet tract. The phase structure of the right ventricular cycle was marked by the appearance of a syndrome of hyperdynamia as detected previously in the adult dogs.

Effect of chronic sodium depletion in dogs with denervated kidneys and hearts

ARTICLESEffect of chronic sodium depletion in dogs with denervated kidneys and heartsLA Brennan, JJ Mulcahy, OA Carretero, RL Malvin, P Geis, and M KayeLA Brennan, JJ Mulcahy, OA Carretero, RL Malvin, P Geis, and M KayePublished Online:01 Dec 1974https://doi.org/10.1152/ajplegacy.1974.227.6.1289MoreSectionsPDF (787 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByIdentification of a Renin Threshold and Its Relationship to Salt Intake in a Patient With Pure Autonomic FailureHypertension, Vol. 30, No. 5Effects of propranolol on the development of renovascular hypertension in the ratAmerican Heart Journal, Vol. 94, No. 1Aldosterone production during dietary sodium restriction and beta-adrenergic blockadeKidney International, Vol. 11, No. 2Control of renin release: A review of experimental evidence and clinical implicationsThe American Journal of Cardiology, Vol. 37, No. 4Hypotensive effect of clonidine during sodium depletion in the rat.Circulation Research, Vol. 37, No. 6 More from this issue > Volume 227Issue 6December 1974Pages 1289-1291 Copyright & PermissionsCopyright © 1974 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1974.227.6.1289PubMed4613187History Published online 1 December 1974 Published in print 1 December 1974 Metrics