[GABA-ergic effects of harman independent of its influence on benzodiazepine receptors].

It has been shown in experiments on rat cortex slices preincubated with 3H-GABA that chlorodiazepoxide (10(-6), 3.10(-5) M) does not change basal and electric stimulation-induced release of the label. It has been also shown that it does not eliminate the autoinhibitory effect of GABA on electric stimulation-induced release of 3H-GABA. However, harmane and some other (but not all) derivatives given at the same concentrations increase 3H-GABA release induced by electric stimulation and abolish the inhibitory effect of GABA without changing or slightly raising spontaneous release of 3H-GABA. It is concluded that harmane enhances the electrically stimulated release of the transmitter by GABAergic axons whatever the effect on benzodiazepine-binding areas of GABA receptors.