Baroreflex control of renin release in spontaneously hypertensive rats after administration of felodipine.

The baroreflex control of heart rate will be rapidly reset to operate at a lower pressure level after blood pressure reduction by felodipine. The present study investigates whether the baroreflex control of renin release in spontaneously hypertensive rats (SHR) will also be reset after prolonged felodipine administration. Conscious SHR, fitted with catheters in the tail artery and vein, were given felodipine intravenously for 5 hours. The initial reflexogenic elevation in plasma renin activity and heart rate caused by felodipine-induced blood pressure reduction were successively normalised with time. Heart rate returned to pre-drug values after 3 hours and plasma renin activity after 5 hours of stable blood pressure reduction. This indicates rapid resetting of baroreflex control of both cardiac and renal function after blood pressure reduction by felodipine.