D2 antagonists in GI
One class of drugs that is used to control motility in the gastrointestinal tract are The D2antagonists. These drugs (such as metoclopramide and domperidone) block inhibitory D2 receptors on myenteric neurons, thereby increasing the release of acetylcholine from nerve terminals. This increase in acetylcholine can stimulate muscarinic-3 receptors, and
Extra info: Most systemic D2 inhibition of acetylcholine-stimulated motility occurs in the upper GI. D2 antagonists are therefore not useful for treating problems in the lower GI.
Extra info: Although D2-antagonists have some influence over all the given answers, it is believed that their effects on the chemo-receptor trigger zone are most important