It was shown in experiments on anesthetized normotensive, spontaneous-hypertensive rats and in those with experimental renovascular hypertension (NR, SHR and RVR, respectively) that intravenous injection of bradykinin (10 micrograms/kg) produces a decrease in arterial pressure and general peripheral vascular resistance. Intra-aortal administration of bradykinin causes hypotension as well. The degree of arterial pressure lowering in hypertensive rats is far greater than in NR. It was recorded that the cardiac component of the baroreflex to short-term aorta occlusion increases in SHR by 133% and RVR by 173%, while NR manifest its reduction by 6%. Angiotensin II (05. micrograms/kg) raises arterial pressure and general peripheral resistance, enhances pressor-reactions and potentiates reactive hyperemia. Activation of the baroreflex is recorded only in NR.