[The role of immunoreactive nerves in the human bladder neck]

VIP-containing nerves have been considered as an inhibitory nerve of non-cholinergic, non-adrenergic action in the bladder neck. Using immunohistochemistry, VIP was stained in the bladder neck in 14 cases which involved 5 cases of bladder neck contracture in addition to 9 cases of benign prostatic hypertrophy (BPH). Consequently, the VIP immunoreactive nerve was not stained in the 4 cases of bladder neck contracture with a large quantity of residual urine which had the fibrosis of bladder neck, but in one case was stained without residual urine. In the BPH, 8 out of 9 cases were stained and they had small residual urine. It was fully stained in the cases without residual urine or with a small volume if they had it. The possible role of VIP in the bladder neck was supposed to be to maintain the bladder neck opening by the strong smooth muscle relaxation.