Receptor for motilin identified in the human gastrointestinal system

Motilin is a 22-amino acid peptide hormone expressed throughout the gastroi ntestinal (GI) tract of humans and other species. It affects gastric motili ty by stimulating interdigestive antrum and duodenal contractions. A hetero trimeric guanosine triphosphate-binding protein (G protein)-coupled recepto r for motilin was isolated from human stomach, and its amino acid sequence was found to be 52 percent identical to the human receptor for growth hormo ne secretagogues. The macrolide antibiotic erythromycin also interacted wit h the cloned motilin receptor, providing a molecular basis for its effects on the human GI tract. The motilin receptor is expressed in enteric neurons of the human duodenum and colon. Development of motilin receptor agonists and antagonists may be useful in the treatment of multiple disorders of GI motility.