ANTAGONISTS OF THE METABOTROPIC GLUTAMATE-RECEPTOR DO NOT PREVENT INDUCTION OF LONG-TERM POTENTIATION IN THE DENTATE GYRUS OF RATS

The effects of two competitive metabotropic glutamate (mGlu) receptor antagonists, (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG) and (S)-4-carboxylphenylglycine (4CPG), were studied on long-term potentiation in the dentate gyrus of rats under urethane anaesthesia. Intracerebroventricular (i.c.v.) injection of MCPG or 4CPG 30 min prior to tetanic stimulation of the perforant path in rats did not affect the induction of long-term potentiation measured by extracellular recording. As a control, i.c.v. injections of the NMDA receptor antagonist, dl(-)-2-amino-5-phosphonopentanoic (dl-AP5), effectively blocked long-term potentiation. These results suggest that the mGlu receptor subtype blocked by MCPG and 4CPG is not involved in long-term potentiation in the dentate gyrus.