Bile acids are able to reduce blood pressure by attenuating the vascular reactivity in spontaneously hypertensive rats

Abstract Effects of the synthetic bile acids on blood pressure were examined in spontaneously hypertensive rats. Continuous intravenous administration of the bile acids at the rate of 1 mg/min for 20 min significantly lowered the blood pressure by 12 mmHg. In order to examine its blood pressure lowering mechanism, the isolated mesenteric arterial perfusion system was employed. Bile acids in the perfusate inhibited vascular reactivity to norepinephrine and KCl in a dose-dependent manner. This inhibitory action diminished as the concentration of potassium in the perfusate decreased. When the perfusate was free from potassium, its inhibitory action completely disappeared. These results in vivo and in vitro studies strongly suggest that bile acids act directly on the vascular beds and attenuate vascular response to norepinephrine.