Cardiac Output in Conscious One-clip, Two-kidney Renovascular Hypertensive Rats

Cardiac output and arterial pressure in the conscious state were observed in one-clip, two-kidney renovascular hypertensive rats with a chronically implanted electromagnetic flow probe and an arterial cannula. Normal Wistar rats were used as controls. At rest, cardiac output per body weight did not show any difference between hypertensive rats and normal controls. This kind of experimental hypertension was maintained entirely by elevation of total peripheral resistance. In transposition response induced by tranposing rats from their home cage to a new cage, after beta adrenoceptor blockade with propranolol, total peripheral resistance remained unchanged in contrast to control rats in which resistance was elevated. This may be due to either a less marked vasoconstriction in the splanchnic area or a greater non-beta adrenergic vasodilatation in the skeletal muscle in transposition response in hypertensive rats than in control rats.