Role of arachidonic acid in the facilitation of glutamate release from rat cerebrocortical synaptosomes independent of metabotropic glutamate receptor responses.

The role of arachidonic acid in the facilitation of glutamate release by the metabotropic glutamate receptor, mGluR, agonist (1S,3R)-1-amino-cyclo-pentane-1,3-dicarboxylate ((1S,3R)-ACP), was investigated in cerebrocortical nerve terminals from adult rats. mGluR activation with the agonist (1S,3R)-ACPD involved a transient increase in the intrasynaptosomal concentration of diacylglycerol that was not altered by the presence of arachidonic acid either in polarized synaptosomes, or in synaptosomes depolarized with 4-aminopyridine. These results suggest that the locus of the arachidonic acid action in the facilitation of glutamate release is downstream of the metabotropic glutamate receptor in the signal transduction pathway.