Effect of vasoactive intestinal peptide on the contractility of the rabbit urinary bladder

Vasoactive intestinal peptide (V. I. P.) has been demonstrated in neuronal elements of smooth muscle organs including the urinary bladder, thus indicating that this peptide may be a neurohumoral transmitter. In isolated strips of rabbit urinary bladder we have demonstrated that V. I. P. causes relaxation. Unlike the relaxant effect of the beta agonist isoproterenol, the inhibition produced by V. I. P. could not be blocked by propranolol. These studies indicate that V. I. P. may play a role in the regulation of bladder contractility.U