The effect of vasoactive intestinal polypeptide on the urinary bladder and taenia coli of the guinea pig.

The effect of vasoactive intestinal polypeptide (VIP) on the contractile activity of the urinary bladder and taenia coli of the guinea pig has been investigated. In the urinary bladder VIP caused a weak contraction and a small potentiation of the nerve-induced contraction. In the taenia coli VIP caused a small relaxation and had no effect on the nerve-induced relaxation of the preparation. The present experiments provide no evidence that VIP fulfills a role as a neurotransmitter in the urinary bladder or taenia coli, but it could be a modulator of transmitter action in the urinary bladder.