[The GABA-ergic component of the anxiolytic action of 1-(2-pyrimidinyl)-piperazine derivatives].

The 1-(2-pyrimidinyl)-piperazine derivatives campirone, campironine, levopironine) evoked hyperpolarizing responses of rat dorsal root ganglion neurons mediated by 5-hydroxytryptamine(1A) receptor activation and, like chlordiazepoxide, potentiated neuronal responses evoked by GABA-depolarizing receptor activation. The drugs studied in the lighted space and threatening situation avoidance tests showed an anxiolytic effect. Picrotoxin was found to be effective in inhibiting the anxiolytic effect of chlordiazepoxide, levopironine and campironine, but it failed to affect the antianxious action of campirone. Whether the GABA-ergic mechanisms may contribute to the anxiolytic action of 1-(2-pyrimidinyl)-piperazine derivatives.