The anxiolytic-like effect of metabotropic glutamate receptor antagonists after intrahippocampal injection in rats.

Using the conflict drinking Vogel test in rats as a model we examined the anxiolytic-like activity, after their intrahippocampal administration of (S)-4-carboxy-3-hydroxyphenyl-glycine (S-4C3H-PG), RS-alpha-methylserine-O-phosphate-monophenyl ester (MSOPPE) and (RS)-alpha-methylserine-O-phosphate (MSOP), the antagonists of the I, the II and the III group of metabotropic glutamate receptors (mGlu receptors), respectively. The results indicate that S-4C3H-PG and MSOP produced a dose-dependent anticonflict effect in rats, which was unrelated to a 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 both mGlu receptor antagonists.