Release of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) from organs of the genitourinary tract in rats.

Calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) was detected in the rat urinary bladder, ureter and vas deferens and was depleted by systemic capsaicin desensitization. Exposure to capsaicin in vitro produced a prompt increase in CGRP-LI outflow in superfusates of these tissues, while a second application of the drug was ineffective indicating desensitization. These findings provide further evidence for a transmitter role of CGRP from peripheral endings of sensory nerves and the involvement of CGRP-LI in the specific motor response to capsaicin in the rat genitourinary tract.