Abstract
The inhibitory effects of cryptolepine and its interaction with prostaglandin E2, indomethacin, adrenaline and acetylcholine have been investigated on the isolated
rabbit duodenum.
Cryptolepine (10-20 µg ml-1) or adrenaline (0.5-1 µg ml-1) or indomethacin (10-20 µg ml-1) abolished or reduced pendular contractions and relaxed the tissue. Cryptolepine
(20 µg ml-1) produced an initial contraction before relaxation of the tissue.
Cryptolepine (10-20 µg ml-1) abolished responses of the duodenum to added prostaglandin E2 and acetylcholine, but failed to reduce prostaglandin production.
The results suggested that cryptolepine antagonises prostaglandin, but has no inhibitory
effect on its synthesis or release.
