Beta-adrenoceptor subtypes in the atrioventricular conducting system and myocardium of spontaneously hypertensive rats: effects of angiotensin-converting enzyme inhibition by perindopril.
Quantitative autoradiography was used to determine the density and distribution of beta 1- and beta 2-adrenoceptors in the atrioventricular (AV) conducting system and surrounding myocardium of spontaneously hypertensive rats (SHR) after chronic infusion of perindopril (1 mg/kg/day) for 14 days by osmotic mini-pumps. Systolic blood pressure (SBP) was measured for a period of 4 weeks (2 weeks before and 2 weeks during perindopril infusion) in control and treated animals. Animals infused with vehicle (water) had a mean SBP of 248 mm Hg (measured on day 29); animals treated with perindopril had lower SBP (121 mm Hg, day 29). Perindopril treatment also prevented development of cardiac hypertrophy in SHR. beta-Adrenoceptor densities were measured in the AV node, His bundle, left and right bundle branches (LB, BB), interventricular and interatrial septa (IVS, IAS), mitral valve (MV), right papillary muscle, left and right ventricles (LV, RV), left and right atria (LA, RA), and apex. Perindopril produced no significant change in beta-adrenoceptors in any cardiac region examined. The results suggest that under experimental conditions in which perindopril treatment prevented cardiac hypertrophy and decreased SBP, there was no significant interaction between the renin-angiotensin system (RAS) and beta-adrenoceptor system in rat heart.
Matthews
J M
JM
Department of Pharmacology, University of Melbourne, Parkville, Australia.
Molenaar
P
P
Summers
R J
RJ
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001345:Autoradiography; D001794:Blood Pressure / Q000187:drug effects; D002036:Bundle of His / Q000737:chemistry / Q000187:drug effects; D006332:Cardiomegaly / Q000517:prevention & control; D004195:Disease Models, Animal; D005260:Female; D006321:Heart / Q000187:drug effects*; D006333:Heart Failure / Q000378:metabolism* / Q000503:physiopathology; D007211:Indoles / Q000494:pharmacology*; D007260:Infusion Pumps; D009206:Myocardium / Q000737:chemistry*; D020913:Perindopril; D051381:Rats; D011918:Rats, Inbred SHR; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000187:drug effects*; D014018:Tissue Distribution
D000806:Angiotensin-Converting Enzyme Inhibitors; D007211:Indoles; D011943:Receptors, Adrenergic, beta; D020913:Perindopril