GABAA ρ receptor mechanisms in the rat amygdala and its role in the modulation of fear and anxiety

Rationale Accumulating evidence for the presence of GABA A ρ receptors within the amygdala which differ from other members of the GABA A receptor family in both subunit composition and functional properties has been recently obtained. Objectives This work was conducted to study whether GABA A ρ receptors may have a putative role in the amygdaloid modulation of fear and anxiety. Results It was found that the bilateral intra-amygdaloid administration (6–240 pmol/side) of (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid, a selective GABA A ρ receptor antagonist, reduced dose-dependently the exploration of the open arms of the elevated plus-maze without affecting locomotion and increased the plasma levels of corticosterone. In contrast, bicuculline in the dose range used (1.8–60 pmol/side) induced seizures, but had no effects on the exploration of the maze. Conclusions It is suggested that GABA A ρ receptors may have a role in the amygdaloid modulation of fear and anxiety.