Effect of pre- and post-treatments with diazepam on the rat brain GABAergic system during anoxic stress and recovery.

Anoxia induced by exposure to N(2) gas for 15, 30, 50 and 60 s showed appearance of varying degrees of restlessness, tremor and convulsive behaviour resulting in mortality of adult rats. Diazepam treatment in pre- and post-anoxic conditions (10 and 20 mg/kg, respectively) has been found to decrease the anoxia-induced mortality rate along with suppression of other abnormal behaviours. In anoxic rats an increase in glutamate (Glu) level was noted. There was no change in the activity of glutamic acid decarboxylase (GAD), but GABA-aminotransferase (GABA-T) activity decreased significantly. In diazepam-treated (pre- and post-anoxic) rats there was an increase in the GAD activity with concomitant increase in ?-aminobutyric acid (GABA) level. GABA-T activity as well as Glu level became normalized. Results indicate that diazepam treatment may have some protecting ability from anoxia-induced imbalance in rat brain glutamatergic and GABAergic functions.