Feeley T M, Clanachan A S, Scott G W
Can J Physiol Pharmacol. 1984 Apr;62(4):356-9. doi: 10.1139/y84-057.
The effects of several preparations of vasoactive intestinal polypeptide (VIP) on the motility of strips of human and guinea pig gallbladder were investigated in vitro. VIP (10(-12) to 10(-6) M) had no measurable effects on the spontaneous activity, resting tone or cholecystokinin-octapeptide induced tone of human gallbladder strips. However, VIP (10(-12) to 10(-6) M) caused biphasic effects on the tone of guinea pig gallbladder strips. At low concentrations (10(-12) to 10(-10) M) contractions were observed that became smaller at higher concentrations (10(-9) to 10(-8) M). At still higher concentrations (10(-7) to 10(-6) M) relaxations were elicited. It appears that VIP is not as potent a relaxant of gallbladder muscle as first described. Human gallbladder tissue was totally unresponsive to the VIP preparations tested.
