Influence of low- and high-pressure baroreceptors on plasma renin activity in humans.
We evaluated effects of the low- and high-pressure baroreceptors on plasma renin activity (immunoassay) using graded lower body suction (LBS) in six healthy men. LBS at -10 and -20 mmHg for 10 min decreased central venous pressure without changing arterial pressure and thereby presumably reduced low- but not high-pressure baroreceptor inhibition of renin release. LBS at these levels produced forearm vasoconstriction, but did not increase renin. LBS at -40 mmHg decreased central venous and arterial pulse pressure and thus reduced both low- and high-pressure baroreceptor inhibition. LBS at this level produced forearm vasoconstriction and tachycardia and increased renin from 2.1 +/- 0.4 (mean +/- SE to 7.4 +/- 1.4 ng.ml-1.h-1 (P less than 0.05). In summary, reduction in low-pressure baroreceptor inhibition in humans did not increase renin in the presence of physiological tonic inhibition from high-pressure baroreceptors. Increases in renin did not occur until there was combined reduction of high- and low-pressure baroreceptor inhibition on plasma renin activity.
D000328:Adult; D001274:Atmospheric Pressure; D002496:Central Venous Pressure; D005542:Forearm / Q000098:blood supply; D006801:Humans; D008297:Male; D010991:Plethysmography; D011311:Pressoreceptors / Q000502:physiology*; D012018:Reflex; D012039:Regional Blood Flow; D012083:Renin / Q000097:blood*; D013396:Suction
D012083:Renin