Stimulation of group II metabotropic glutamate receptors or inhibition of group I ones exerts anxiolytic-like effects in rats

Using the conflict drinking Vogel test in rats as a model we examined the a nxiolytic-like activity of (S)-4-carboxyphenylglycine (S-4CPG), an antagoni st of group I metabotropic glutamate receptors (mGlu receptors), of (RS)-al pha-methylserine-O-phosphate-monophenyl ester (MSOPPE), an antagonist of gr oup II mGlu receptors, and of (2S,1'S,2'S)-2-(carboxycyclopropyl)glycine (L -CCG-I), an agonist of group II mGlu receptors. The obtained results indica te that intrahippocampal administration of S-4CPG and L-CCG-I, but not MSOP PE to rats produces a dose-dependent anticonflict effect, which is unrelate d to the reduced perception of the stimulus or to an increased thirst drive . The hippocampus may be one of the neuroanatomical sites of the anxiolytic -like effects of either agent.