Metabotropic glutamate receptors stimulate phospholipase D via different pathways in the adult and neonate rat hippocampus

In order to characterize the ontogenetic profile of metabotropic glutamate (mGlu) receptors coupled to phospholipase D (PLD) we examined the effects o f selected mGlu agents on PLD activity in immature and adult rat hippocampu s. The group I mGlu receptor agonist 3,5-dihydroxyphenylglycine stimulated PLD in immature tissue, but reduced the PLD response evoked by the nonselec tive mGlu receptor agonist (1S,3R)-1-an-aminocyclopentane-1,3-dicarboxylate [(1S,3R)-ACPD] in adult hippocampus. (2R,1'S,2'R,3'S)-2-(2'-Carboxy-3'-phe nylcyclopropyl) glycine (PCCG-13), a recently characterized selective antag onist of PLD-coupled mGlu receptors, displayed a much greater activity in r educing the PLD response to (1S,3R)-ACPD in adult than in neonate hippocamp us. Our results lend support to the hypothesis that glutamatergic activatio n of PLD in the rat hippocampus is developmentally regulated.