Dietary potassium, blood pressure and peripheral adrenergic responsiveness in the deoxycorticosterone acetate-salt rat.
This study investigated the effect of 6 weeks of dietary potassium (K) supplementation on blood pressure and in vivo and in vitro peripheral adrenergic responsiveness in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Dietary K supplementation did not affect the development of hypertension in DOCA-salt rats. The chronotropic and dipsogenic responses to isoproterenol (ISO) administration were significantly decreased in DOCA-salt rats. Addition of K to the diet resulted in a complete normalization of both of these responses so that they were similar to controls. Aortic smooth muscle from DOCA-salt rats exhibited a significant reduction in the relaxation response to ISO. Dietary K supplementation resulted in only a partial normalization of this response. Enhanced norepinephrine responsiveness was observed in aortic smooth muscle from DOCA-salt rats, but was not affected by dietary K supplementation. These results show that: 1) a 0.5% dietary K supplementation in DOCA-salt rats does not prevent the development of hypertension, 2) the decreased peripheral beta-adrenergic responsiveness observed in DOCA-salt rats is partially normalized by the addition of K to the diet, and 3) the increased alpha- adrenergic sensitivity is not affected by the 0.5% dietary K supplementation in the DOCA-salt rat. It is concluded that dietary K supplementation has differential effects on peripheral alpha- and beta- adrenergic responsiveness in the DOCA-salt rat. These actions may be related to the lack of an antihypertensive effect of K in the present study.
Soltis
E E
EE
Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville 32610.
Iloeje
E
E
Katovich
M J
MJ
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003900:Desoxycorticosterone; D004032:Diet; D004195:Disease Models, Animal; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology*; D011188:Potassium / Q000008:administration & dosage*; D051381:Rats; D011919:Rats, Inbred Strains
D003900:Desoxycorticosterone; D007545:Isoproterenol; D011188:Potassium