The influence of gabaergic system on cataleptogenic action of analgesics and haloperidol

The effect of agonists and antagonists of the gabaergic system on catalepsy induced by morphine, fentanyl and haloperidol was investigated in the rat. The compounds inhibiting gabaergic neurotransmission, bicuculline and picrotoxin, given in subconvulsive doses (0.1-0.5 mg/kg) in general do not evidently affect cataleptogenic effects of the analgesics and haloperidol. Of the gabaergic agonists muscimol (0.2-0.5 mg/kg) potentiates only the haloperidol catalepsy, without changing the action of analgesics. Aminooxyacetic acid (AOAA, 25 mg/kg) markedly potentiated the catalepsy brought about by analgesics, while weakly and insignificantly facilitated that induced by haloperidol. Baclofen in a low dose (1 mg/kg) antagonized the action of haloperidol and fentanyl, whereas in higher doses (2-8 mg/kg) it did not visibly affect the action of any investigated drugs. Thus the action of gabaergic agonists and antagonists on the analgesic and haloperidol catalepsy varies, depending on the dose and kind of the agent affecting the gabaergic system.