Document Detail

Preserved cardiac beta-adrenergic sensitivity in early renovascular hypertension.
MedLine Citation:
PMID:  3032789     Owner:  NLM     Status:  MEDLINE    
To determine the mechanism of blunted sympathetic reflex responses in early renovascular hypertension, we measured inotropic and chronotropic responses of the heart to beta-adrenergic stimulation in vivo and myocardial beta-adrenergic receptor number and adenylate cyclase activity in 10 dogs during an early stage of one-kidney renal hypertension. Mean aortic pressure was higher in the hypertensive dogs (152 +/- 4 mm Hg) than in eight sham-operated dogs (122 +/- 1 mm Hg; p less than 0.001), but heart rate, cardiac output, and left atrial pressure did not differ between the two groups. Blood pressure reduction with a direct-acting vasodilator, pinacidil, resulted in marked increases in heart rate (+97 +/- 12 beats/min) and rate of change of left ventricular pressure (dP/dt; +1447 +/- 367 mm Hg/sec) in normotensive dogs but only blunted heart rate (+54 +/- 12 beats/min) and minimal left ventricular dP/dt (+376 +/- 264 mm Hg/sec) responses in hypertensive dogs. In contrast, intravenously administered isoproterenol produced similar increases in heart rate and left ventricular dP/dt in the two groups. These two groups also did not differ in either left ventricular beta-adrenergic receptor number and affinity or basal, isoproterenol-stimulated, and fluoride-stimulated adenylate cyclase activity. Thus, despite blunted reflex responses to blood pressure reduction, hypertensive dogs showed neither reduction in chronotropic and inotropic responses to direct beta-adrenergic stimulation nor beta-adrenergic desensitization of the myocardium, as assessed by beta-adrenergic receptor number and adenylate cyclase activity. Blunted reflex responses in this model of early hypertension must be due to factors operating at some locus other than the beta-adrenergic receptor-adenylate cyclase complex.
W R Davidson; S Kawashima; S P Banerjee; C S Liang
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Hypertension     Volume:  9     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:  1987 May 
Date Detail:
Created Date:  1987-06-05     Completed Date:  1987-06-05     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  467-72     Citation Subset:  IM    
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MeSH Terms
Adenylate Cyclase / metabolism
Blood Pressure / drug effects*
Guanidines / pharmacology*
Heart Rate / drug effects
Heart Ventricles / metabolism
Hemodynamics / drug effects
Hypertension, Renovascular / physiopathology*
Isoproterenol / pharmacology*
Myocardium / metabolism
Norepinephrine / metabolism
Receptors, Adrenergic, beta / drug effects*
Vasodilator Agents / pharmacology*
Grant Support
Reg. No./Substance:
0/Guanidines; 0/Receptors, Adrenergic, beta; 0/Vasodilator Agents; 51-41-2/Norepinephrine; 7683-59-2/Isoproterenol; 85371-64-8/Pinacidil; EC Cyclase

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