Calcitonin gene-related peptide in the hamster seminal vesicle and coagulating gland: an immunohistochemical, autoradiographical, and pharmacological study.

The distribution of calcitonin gene-related peptide (CGRP)-immunoreactive nerves and CGRP binding sites, as well as the effect of CGRP on the muscle tension, was studied in the hamster seminal vesicle and coagulating gland. The use of an immunofluorescence staining technique on cryostat sections revealed that in the hamster seminal vesicle and coagulating gland, CGRP-positive nerve fibers are found in the connective interstitium and in the muscular and mucosal layers. Using an in vitro receptor autoradiographic technique, CGRP binding sites were found associated with the muscular coat. CGRP (10 pM to 1 microM) relaxed the seminal vesicle and the coagulating gland precontracted by either noradrenaline (10-30 microM) or the alpha 1-agonist, phenylephrine (10 microM). In preparations contracted by carbachol (10 microM), CGRP relaxed the seminal vesicle but not the coagulating gland. In both preparations, CGRP (1 microM) did not affect the muscle resting tension. These results suggest that CGRP may act as an inhibitory modulator of the autonomic control of contractility in the male accessory sex glands of the hamster.