Erythromycin acts on which receptor in GITract -

Ans. is 'a' i.e., Motilin * Erythromycin stimulates motilin (an upper gastrointestinal peptide hormone) receptors in the g.i.t.--thereby induces gastric contractions, hastens gastric emptying and promotes intestinal motility without significant effect on colonic motility.* On the basis of this action erythromycin has been occasionally used to afford short-term symptomatic relief in diabetic gastroparesis. However, tolerance quickly develops to this action (probably due to receptor down- regulation) and undesirable alteration of bacterial flora limit use of erythromycin as a prokinetic agent. Contribution of this action to the g.i. side effects of erythromycin is not known.