Contractile effects of tetradecapeptide renin substrate on rat femoral resistance vessels.
The effect of products of the renin-angiotensin system on the contractile response of rat resistance vessels (internal diameter approximately 200 microns) has been investigated. The vessels were isolated from the femoral bed and segments of the vessels were mounted on an isometric myograph. The vessels responded in a concentration-dependent manner to synthetic tetradecapeptide (TDP) renin substrate, angiotensin I (ANG I) and angiotensin II (ANG II), the responses to all these substances being inhibited by saralasin (0.1 mumol/l). The responses to ANG I, but not those to TDP renin substrate, were inhibited by captopril (1 mmol/l). In contrast, the non-specific protease inhibitor aprotinin had an inhibitory effect on responses to TDP renin substrate. The results suggest that TDP renin substrate is converted to ANG II by a process that does not involve metabolism of ANG I.
D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000808:Angiotensinogen / Q000494:pharmacology*; D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D011921:Rats, Inbred WKY; D014655:Vascular Resistance / Q000187:drug effects
D000808:Angiotensinogen; D000804:Angiotensin II; D000803:Angiotensin I; D007611:Aprotinin; D002216:Captopril