Activation of muscarinic receptors stimulates the release of choline from brain slices.

The effect of several agents known to interact with muscarinic acetylcholine receptors on the release of choline from slices of rat corpus striatum into the incubation medium has been investigated. The amount of released choline was increased if choline, acetylcholine, or oxotremorine had been added to the incubation medium. Atropine blocked the effects of acetylcholine and oxotremorine; it was not tested with choline. It is proposed that the increased release of choline is due to an increased hydrolysis of phosphatidylcholine, brought about by the activation of muscarinic acetylcholine receptors.