Functional arterial baroreflex attenuates the effects of antihypertensive drugs in conscious rats.
The present work was designed to observe the influences of arterial baroreflex (ABR) function on cardiovascular effects produced by four routinely used antihypertensive drugs in conscious rats. A low ABR model was obtained by the performance of sinoaortic denervation (SAD). The doses of the four drugs were as follows: nifedipine (1.5, 3.0 mg/kg), captopril (50, 100 mg/kg), atenolol (10, 20 mg/kg), and hydrochlorothiazide (20, 40 mg/kg). They were administered via an intra-gastric catheter. Compared with sham-operated rats, SAD significantly increased blood pressure variability about 2 times without modification of blood pressure level. The decrease in blood pressure level induced by the four tested drugs was larger in SAD rats than in sham-operated rats, which decreased to about 10 mmHg. Pulse interval was not changed by the treatment of captopril, but prolonged by atenolol in both sham-operated and SAD rats. In sham-operated groups, treatment of both nifedipine and hydrochlorothiazide decreased pulse interval. Whereas in sinoaortic denervated ones, this tachycardia was prevented. Among the four tested drugs, it was found that only nifedipine and atenolol significantly decreased blood pressure variability in SAD rats. It can be concluded that arterial baroreflex function was able to attenuate the hypotensive effects produced by antihypertensive drugs in conscious rats.
Department of Pharmacology, Second Military Medical University, China.
Jin
J
Wang
Fu-Ming
FM
Shen
Xiao-Fei
XF
Zhang
Min-Wei
MW
Wang
Ding-Feng
DF
Su
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000294:innervation; D001262:Atenolol / Q000494:pharmacology; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects*; D002216:Captopril / Q000494:pharmacology; D002346:Carotid Sinus / Q000294:innervation; D003714:Denervation; D004305:Dose-Response Relationship, Drug; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D011674:Pulse; D051381:Rats; D017207:Rats, Sprague-Dawley
D000959:Antihypertensive Agents; D001262:Atenolol; D002216:Captopril; D009543:Nifedipine