ACTIVATION OF GROUP-II METABOTROPIC GLUTAMATE RECEPTORS BLOCKS INDUCTION OF LONG-TERM POTENTIATION AND DEPOTENTIATION IN AREA CA1 OF THE RAT IN-VIVO

The metabotropic glutamate receptor group-II agonist (1S,3S)-1-aminocy clopentane-1,3-dicarboxylic acid (1S,3S-ACPD; 5 mu l/10 mM, i.c.v.) pr evented the induction of long-term potentiation and depotentiation in the CAI area of the hippocampus in urethane-anaesthetised rats. These effects were prevented by the group-II metabotropic glutamate receptor antagonists ethyl-(2S,3S,4S)-alpha-(carboxycyclopropyl)glycine (MCCG; 5 mu l/100 mM) and (RS)-alpha-methyl-4-tetrazolylphenylglycine (MTPG; 5 mu l/500 mM). The group-I antagonist (RS)-1-aminoindan-1,5-dicarbox ylic acid (AIDA; 5 mu l/200 mM) or the group-III antagonist alpha-meth yl-L-2-amino-4-phosphonobutyrate (MAP4; 5 mu l/100 mM) did not affect the block of the induction of long-term potentiation by 1S,3S-ACPD. It is concluded that activation of group-II metabotropic glutamate recep tors can block both high-frequency stimulation-induced long-term poten tiation and low-frequency stimulation-induced depotentiation in the CA 1 area, in vivo. (C) 1997 Elsevier Science B.V.