Specific calcitonin gene-related peptide binding sites present throughout rat intestine

Calcitonin gene-related peptide is found extensively in the innervation of the intestine and has potent pharmacological effects on secretion, blood fl ow, and motility. Although essential for assessing the physiological signif icance of CGRP, detailed information concerning the distribution of its rec eptor(s) within the intestine is lacking. By using autoradiographic methods , we identified specific binding sites for I-125-tyr(0)-CGRP-alpha in all r egions of the rat small and large intestine. Particularly dense saturatable binding is observed within the lamina propria. There is moderate saturatib le binding in the myenteric plexuses. These findings clearly support the no tion that CGRP has a neuroeffector role in intestinal functions. (C) 1999 E lsevier Science Inc. All rights reserved.