INVITRO EFFECT OF PIRENZEPINE ON MOTILITY OF CANINE GALLBLADDER

Abstract— The action of pirenzepine as an antimuscarinic drug has been investigated on motor responses of muscle strips in the canine gall‐bladder. Pirenzepine was further used to examine whether gall‐bladder motor responses to synthetic sulphated cholecystokinin octapeptide (CCK‐8) are sensitive to pirenzepine. Pirenzepine (10−9‐10−5 M) antagonized muscle contractions in response to acetylcholine (10−9‐10−2 M) and CCK‐8 (10−11‐10−6 M) in a significant manner. These findings indicate that pirenzepine is a potent antagonist of two substances that are the principal contractile mediators of gall‐bladder contraction and suggest that long‐term administration of pirenzepine could contribute to stasis of the gall‐bladder. 1990 Royal Pharmaceutical Society of Great Britain