Immunoneutralization suggests that calcitonin gene related peptide regulates gastric emptying in the rat

The role of calcitonin gene related peptide (CGRP) in controlling gastric emptying was examined in conscious gastric fistual rats. Rats were immunized with CGRP conjugated to thyroglobulin to produce circulating antibodies for neutralization of the endogenous peptide; control rats received carrier thyroglobulin alone. In the latter acid, protein and hypertonic solutions delayed gastric emptying; in rats with CGRP antibodies the action of acid and hyperosmolal solutions, but not protein, was reversed. The data are compatible with the idea that acid and hyperosmolal solutions release CGRP at the peripheral terminals of visceral afferents in the upper gastrointestinal tract which in turn modifies motility to slow gastric emptying.