PROLINE-GLUTAMATE INTERACTIONS IN THE CNS

1. Crude synaptosomes (P-2) and synaptosomal membranes were prepared f rom normal C57/B110 mouse brains and Wistar rats respectively. 2. [H-3 ]Pro binding to mouse brain synaptic membranes was examined in the pre sence of competitive NMDA antagonist, MK-801, or HA-966. Conversely, t he effects of I-proline on [H-3]MK-801 binding were also probed. The e ffects of I-proline on glutamate medicated [Ca+2](i) levels were teste d. 3. The authors could not detect any effect of proline on glutamate- mediated [CA(+2)](i) levels using FURA-2 in synaptosomes or neuroblast oma cells. 4. NMDA competitive antagonists, AP-7, CPP, and CGS 19755 i nhibit [H-3]Pro binding to mouse brain synaptic membranes. 5. MK-801, a NMDA channel blocker, also inhibits [H-3]Pro binding, but 200 mM pro line is incapable of inhibiting [H-3]MK-801 binding. 6. HA-966, a glyc ine site partial agonist inhibits [H-3]Pro binding. Proline has modest effects on [H-3]glycine binding.