Vasoactive intestinal polypeptide in the normal and unstable bladder.

The possible involvement in idiopathic detrusor instability of a newly discovered type of autonomic nerve containing vasoactive intestinal polypeptide (VIP) has been studied. Immunocytochemistry and radioimmunoassay, using specific antibodies against VIP, were carried out on 20 biopsy specimens from the bladders of patients with detrusor instability and 20 specimens from control patients. The concentration of VIP in the unstable bladders was found to be markedly reduced from 36.52 +/- 4.8 pmol/g (mean +/- SEM) to 7.62 +/- 1.84 pmol/g (P less than 0.01). The number of VIP immunoreactive nerves was greatly decreased in all of the layers but particularly in the muscle layer of the unstable bladder in comparison with the controls. These findings may provide important information about the mechanism of this disorder.