ACETYLCHOLINE POTENTIATES RESPONSES TO N-METHYL-D-ASPARTATE IN THE RAT HIPPOCAMPUS

The effect of acetylcholine (ACh) on intracellular responses to ionophoretic application of N-methyl-d-aspartate (NMDA) was examined in rat hippocampal slice. Recordings were obtained from CA1 neurons under current- and voltage-clamp conditions. Drugs were applied topically by ionophoretic and microdrop techniques. ACh produced an atropine-sensitive potentiation of responses to NMDA. The effect of ACh on NMDA receptor-mediated responses was independent of changes in voltage or potassium conductances caused by ACh. ACh also potentiated responses to l-glutamate but not to kainate or quisqualate. This effect was blocked by dl-2-amino-5-phosphonovalerate (2-APV), an NMDA receptor antagonist. We conclude that ACh, acting on muscarinic receptors, potentiates selectively, the NMDA subclass of l-glutamate receptor. © 1990.