[GABA-ergic mechanisms of the action of ketamine on the structures of the hippocampo-reticulo-neocortical system of the brain].

In freely mobile rabbits with electrodes preliminarily implanted in the brain structures ketamine (5 mg/kg intravenously or 20 mg/kg intramuscularly) exhibited properties of GABA receptor agonist decreasing the direct excitability of the mesencephalic reticular formation and periaqueductal gray matter and reducing their activating effect on the frontal cortex (FC) and dorsal region of the hippocamp (DH). GABA-mimetics (muscimol, baclofen, aminooxyacetic acid) as well as GABA system antagonists (bicuculline, thiosemicarbazide) attenuated ketamine action at the level of DH and especially FC.