Angiotensin-converting enzyme, bradykinin, angiotensin, and cerebral vessel reactivity.
Bradykinin (BK) produced concentration-related relaxations of cat middle cerebral arteries and was ineffective in cat basilar arteries. On rabbit basilar arteries, BK initially produced concentration-related relaxations; however, when repeated at 2-hour intervals, BK eventually produced pure contractile responses. After preincubation of the tissues with cycloheximide, BK produced reproducible relaxation responses. The angiotensin-converting enzyme inhibitors, SQ 14,225, BPP5a, and BPP9a, had no effect on the concentration-effect curves of BK, AII, or 5-HT with any of the preparations, but responses to AI were inhibited. These results suggest that, in these tissues, angiotensin-converting enzyme is important for conversion of AI to AII, but apparently not for the degradation of BK.
D000803:Angiotensin I / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism; D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins / Q000378:metabolism*; D000818:Animals; D001488:Basilar Artery / Q000378:metabolism; D001920:Bradykinin / Q000378:metabolism*; D002216:Captopril / Q000494:pharmacology; D002536:Cerebral Arteries / Q000378:metabolism*; D005260:Female; D008297:Male; D009119:Muscle Contraction; D009126:Muscle Relaxation; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011817:Rabbits; D051381:Rats
D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D000804:Angiotensin II; D000803:Angiotensin I; D002216:Captopril; D007703:Peptidyl-Dipeptidase A; D001920:Bradykinin