INCREASING-CURRENT ELECTROSHOCK SEIZURE TEST - A NEW METHOD FOR ASSESSMENT OF ANTI-CONVULSANT AND PRO-CONVULSANT ACTIVITIES OF DRUGS IN MICE

We developed the increasing-current electroshock seizure (ICES) test, a new method for assessment of anti- and pro-convulsant activities of drugs in mice. In this method, a single train of pulses (square wave, 5 msec, 20 Hz) of linearly increasing intensity from 5 to 30 mA (incre ment of 0.1 mA/0.1 sec, i.e., 5-30 mA in 25 sec) was applied via ear e lectrodes. The current at which tonic hindlimb extension occurred was recorded as the seizure threshold. Thus, this method allows determinat ion of the seizure threshold current for individual animals. Carbamaze pine, phenytoin, valproate, phenobarbital, diazepam, and morphine all increased the seizure threshold current in a dose-dependent manner, wh ereas ethosuximide was not effective. The seizure threshold current de creased after treatment with reserpine, chlorpromazine, aminophylline, strychnine, pentylenetetrazol, bicuculline, picrotoxin, and ethyl-bet a-carboline-3-carboxylate (beta-CCE). These results indicate that the ICES test, like the maximal electroshock seizure test, is a model of g rand mal-type seizure and is useful for evaluation of both the anti- a nd pro-convulsant activities of drugs.