Activation of the following type of receptors present on myenteric neurons by metoclopramide is primarily responsible for the enhanced acetylcholine release and improving gastric motility:
(Ref: KDT 6/e p646, 647) Gastric motility is increased by ACh. Release of this neurotransmitter is enhanced by 5HT4 receptor stimulation and 5HT3 and D2 receptor antagonism.
Muscarine M1
Serotonergic 5-HT3
Serotonergic 5-HT4
Dopaminergic D2
Other topics and Adverse effects