Role of GABA in the anti-aversive action of anxiolytics.

The above results with intracerebral drug injection and electrical brain stimulation in rats indicate that enhancement of GABAergic activity in the dorsal CG or in the MH raises the threshold of electrical stimulation inducing aversive behavior when applied to these brain areas. Conversely, drug-induced reduction of GABA action in the dorsal CG or in the MH leads to aversive-like behavioral changes. Therefore, GABAergic fibers seem to exert tonic inhibition on neuronal groups in the CG and MH integrating aversive behavioral states. Anxiolytics may cause anti-aversive effects by enhancing this GABAergic modulation. As discussed elsewhere, serotonergic and opioid mechanisms are also likely to operate in periventricular brain areas. In conjunction with GABAergic mechanisms, they may be involved in the pathophysiology of anxiety, panic attacks and pain, as well as in the therapeutic action of anxiolytics, anti-panic drugs and centrally-acting analgesics.