),2'(R),3'(R))-2-(2,3-DICARBOXYCYCLOPROPYL)GLYCINE ENHANCES QUISQUALATE-STIMULATED INOSITOL PHOSPHOLIPID HYDROLYSIS IN HIPPOCAMPAL SLICES

In adult rat hippocampal slices, S,1'R,2R',3R')-2-(2,3-dicarboxyxyclop ropyl)glycine (DCG-IV) did not affect the basal hydrolysis of polyphos phoinositides but dramatically enhanced (EC50 value = 30 nM) the stimu lation of [H-3]inositol monophosphate (InsP) formation by quisqualate, without substantially affecting the stimulation produced by maximal c oncentrations of 1S,3R-amino-cyclopentane-1,3-dicarboxylic acid (ACPD) or carbamylcholine. pha-Amino-3-hydroxy-5-methylisoxazole-4-propionat e (AMPA) was virtually devoid of activity on [H-3]InsP formation, eith er in the absence or presence of DCG-IV. These results suggest that DC G-IV acts, directly or indirectly, as a positive modulator of metabotr opic glutamate receptors in the rat hippocampus.