The effect of captopril on the superior mesenteric artery and portal venous blood flow in normal man.
1. Measurements of superior mesenteric artery and portal venous blood flow were made non-invasively along with systemic and other regional (cardiac index, forearm and cutaneous blood flow) vascular responses to acute ingestion of the ACE inhibitor captopril (50 mg) or placebo (50 mg vitamin C), in 12 healthy subjects while supine and during head-up tilt. 2. After captopril, superior mesenteric artery and portal blood flow rose markedly with a reduction in superior mesenteric artery vascular resistance. Supine blood pressure was unchanged but cardiac index and forearm blood flow rose; during head-up tilt, blood pressure fell in some subjects. 3. There was a rise in levels of plasma renin activity and a fall in levels of plasma angiotensin II after captopril. After placebo, there were no significant changes in splanchnic blood flow, systemic or other regional responses and in biochemical measurements, while supine. 4. Our studies indicate that captopril is a potent dilator of the splanchnic vascular bed and suggest that this action may contribute to its therapeutic effects. The studies indicate a role for angiotensin II in the control of this large vascular bed although other agents (bradykinin, prostacyclin) may contribute.
Ray-Chaudhuri
K
K
Department of Medicine, St Mary's Hospital Medical School/Imperial College of Science, Technology and Medicine, London, UK.
Thomaides
T
T
Maule
S
S
Watson
L
L
Lowe
S
S
Mathias
C J
CJ
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D002302:Cardiac Output / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006728:Hormones / Q000097:blood; D006801:Humans; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects*; D008875:Middle Aged; D018377:Neurotransmitter Agents / Q000097:blood; D011169:Portal Vein / Q000187:drug effects*; D011187:Posture; D011674:Pulse / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D013318:Stroke Volume / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects
D006728:Hormones; D018377:Neurotransmitter Agents; D002216:Captopril