ATP RELEASE CAUSED BY BRADYKININ, SUBSTANCE-P AND HISTAMINE FROM INTACT AND CULTURED SMOOTH MUSCLES OF GUINEA-PIG VAS-DEFERENS

Histamine (60 mu M) produced ATP release from segments of guinea-pig v as deferens which was blocked by pyrilamine and triprolidine, H-1-bloc kers, but not by ranitidine, an H-2-blocker. The evoked-release was in hibited by the mitochondrial inhibitors, carbonyl cyanide-m-chlorophen ylhydrazone (CCCP) and oligomycin. Bradykinin (BK) and substance P (SP ) also caused substantial and moderate release of ATP, respectively Th e BK-evoked release of ATP was inhibited by HOE140, a B-2-antagonist, but not by [Des-Arg(10)] HOE140, a B-1-antagonist. On the other hand, VIP, angiotensin Il (AII) and cholecystokinin-octapeptide (CCK-8) fail ed to elicit a measurable release of ATP. Histamine and BK also enhanc ed the release of ATP from superfused cultured smooth muscle cells. Th ese results suggest that ATP may be released as an autacoid from the s mooth muscles in the presence of these chemical mediators.