Metoclopramide has the following actions EXCEPT:

(Ref: KDT 6/e p643) Metoclopramide is a prokinetic and anti-emetic drug. It acts by blocking D2 and 5-HT3 receptors and stimulating 5-HT4 receptors. D2 receptors are normally inhibitory to the release of ACh. Metoclopramide enhances ACh release by blocking these inhibitory D2 receptors. Due to increased release of ACh, there is increase in gastric motility and LES tone. Prokinetic action can thus be blocked by atropine. Metoclopramide has no effect on colonic motility.