INFLUENCE OF CARBAMAZEPINE AND PHENYTOIN ON SPONTANEOUS ACTIVITY OF CEREBELLAR NEURONS

Action of carbamazepine (50 mg/kg i.p.) and phenytoin (60 mg/kg i.p.) on the activity of cerebellar neurones was studied in rats under ureth ane anaesthesia. Carbamazepine markedly decreased the firing frequency of all ten neurones recorded continually before and after drug admini stration. The same conclusion was reached when a group of 53 cells rec orded before drug administration was compared with 48 neurones recorde d after carbamazepine administration only. The effects of phenytoin we re ambiguous - a decrease as well as an increase in frequency was reco rded. The solvent used did not change cerebellar unit activity. Cerebe llum cannot be considered as a possible target structure for phenytoin but it might be a target for carbamazepine action.