Inhibition of high-affinity [3H]L-proline binding to rat brain membranes by 2-amino-7-phosphonoheptanoic acid

L-Glutamate and 2-amino-7-phosphonoheptanoic acid [corrected] (AP-7) (10(-9) to 10(-6) M), a competitive NMDA (N-methyl-D-aspartate) antagonist, inhibit approximately 60% of [3H]L-proline binding to rat membranes from midbrain. In hippocampal membranes, AP-7 inhibits proline binding by 80%, while in cerebellar membranes AP-7 had little effect. These results are indicative of the possible neuromodulatory role of proline in the central nervous system, possibly through the NMDA receptor(s).