ADAPTATION OF THE NMDA RECEPTOR IN RAT CORTEX FOLLOWING CHRONIC ELECTROCONVULSIVE SHOCK OR IMIPRAMINE

Chronic (14 days) administration of either imipramine or electroconvul sive shock effected significant changes in the ligand binding properti es of the NMDA (N-methyl-D-aspartate) receptor complex in rat cortex. These changes were manifested as: (1) a reduction in the potency of gl ycine to inhibit the binding of 5,7-dichloro[H-3]kynurenic acid to str ychnine-insensitive glycine receptors; and (2) a reduction in the prop ortion of high affinity, glycine-displaceable [H-3]CGP-39653 binding t o NMDA receptors. Chronic electroconvulsive shock, but not imipramine treatment also reduced the density of [H-3]CGP-39653 binding sites in cortical membranes. These findings demonstrate that the ability of chr onic antidepressant treatments to induce adaptive changes in the glyci ne and glutamate regulatory sites of the NMDA receptor is not species specific, since it obtains in rats as well as mice.