Motilin is a polypeptide having 22 amino acids.
It is secreted by enterochromaffin cells and Mo cells in the stomach, small intestine and colon.
- causes contraction of the smooth muscles of the stomach and intestine
- it is th e main regulator of the migrating motor complexes (MMCs); MMCs control the gastrointestinal motility between meals (i.e. in the inter-digestive phase). The blood level of motilin increases at intervals of about 100 minutes in the inter-digestive phase.
- Mechanism of Actions
Motilin acts on G protein-coupled receptors present on the neurons in the duodenum and colon. erythromycin binds to these motilin receptors; thus, it may be useful in patients with decreased gastrointestinal motility.
Neurotensin is a polypeptide having 13 amino acids.
It is secreted from neurons and cells in ileum; its release is stimulated by fatty acids
i. inhibits GI motility
ii. increases blood flow in ileum