THE MGLURS GROUP-II AGONIST (2S,3S,4S)-ALPHA-CARBOXYCYCLOPROPYL-GLYCINE INDUCES CATALEPSY IN THE RAT, WHICH IS PRONOUNCEDLY ANTAGONIZED BY DIZOCILPINE AND D,L-AMPHETAMINE

Glutamate in the basal ganglia has important roles in the regulation o f motor processes and this is the first study on the role of inhibitor y, group II, metabotropic glutamate receptors (mGluRs) for motor behav iour. The group II agonist (2S,3S,4S)-alpha carboxycyclopropyl-glycine (L-CCG I) dose dependently induced catalepsy, infused intracerebroven tricular (i.c.v.) in rats. The catalepsy was antagonised by dizocilpin e and D,L-amphetamine, i.e. by N-methyl-D-aspartate receptor blockade and dopamine receptor activation, respectively. Psychotomimetic side e ffects limit the clinical use of previously suggested postsynaptic app roaches to reduce pathological glutamatergic overactivation, as occuri ng in epilepsy, ischemia or trauma, but group II agonists provide a ne w presynaptic approach. Since the catalepsy-induction predicts a lack of psychotomimetic side effects, this study indicates that presynaptic approaches on mGluRs may be more suitable in these situations. (C) 19 98 Elsevier Science Ireland Ltd. All rights reserved.