Role of renin-angiotensin and sympathetic nervous systems in the chronic phase of two-kidney, one-clip hypertension in rats.
The purpose of the present study was to examine the role of the renin-angiotensin and the sympathetic nervous systems during the chronic phase (greater than 16 weeks) of two-kidney, one-clip hypertension in conscious unrestrained rats. During this phase, the mean arterial pressure (MAP) (p less than 0.001) and plasma angiotensin II (31.9 +/- 1.5 to 125.8 +/- 19.9 pg/ml, p less than 0.005) were significantly increased as compared to normotensive group. Converting enzyme inhibition by captopril produced a significant decrease of MAP (181.2 +/- 8.2 to 140.0 +/- 5.5 mmHg, p less than 0.001). This hypotensive response was similar when aprotinin (a Kallikrein inhibitor) and captopril were infused simultaneously. Alpha 1-adrenergic receptor blockade by phenoxybenzamine (POB) significantly decreased but did not normalize MAP (179.8 +/- 12.4 to 135.8 +/- 10.4 mmHg, p less than 0.001). However, when infused after POB, captopril induced a further decrease of MAP to 86.7 +/- 9.4 mmHg (p less than 0.001). This MAP level was not different from that found in normotensive rats after infusion of the two drugs (83.2 +/- 5.3 mmHg). These results suggest that both the renin-angiotensin system and the sympathetic nervous system, by activating peripheral alpha 1-adrenergic receptors, maintain the high blood pressure during the chronic phase (greater than 16 weeks) of two-kidney, one-clip hypertension in conscious rats.
Salazar
F J
FJ
Ubeda
M
M
Salom
M G
MG
Carbonell
L F
LF
Garcia-Estan
J
J
Quesada
T
T
D000804:Angiotensin II / Q000097:blood; D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D002216:Captopril / Q000494:pharmacology; D006977:Hypertension, Renal / Q000097:blood / Q000503:physiopathology*; D007700:Kinetics; D008297:Male; D010643:Phenoxybenzamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012084:Renin-Angiotensin System; D013564:Sympathetic Nervous System / Q000503:physiopathology*
D010643:Phenoxybenzamine; D000804:Angiotensin II; D007611:Aprotinin; D002216:Captopril