Chronic administration of MK-801 and the NMDA receptor: further evidence for reduced sensitivity of the primary acceptor site from studies with the cortical wedge preparation.

Cortical slices removed from rats pre-treated with MK-901 0.5 mg kg-1 twice a day for 7 days had reduced responses to N-methyl-D-aspartate (NMDA) relative to quisqualate and glutamate compared with control animals. Potencies of competitive (CPMP) and non-competitive (ketamine) NMDA antagonists appeared unchanged. These changes are consistent with a reduced density of NMDA receptors.