The seizure-inducing properties of two pyrethroids were assessed by pentylenetetrazol (PTZ) seizure models (repeated ip, sprathreshold ip, and iv), and electrical kindling of the amygdala. The efficacy of po versus ip routes of deltamethrin administration was compared using iv-PTZ administration and tests of locomotor activity in a figure-eight maze. The Type I pyrethroid, cismethrin (8 or 15 mg/kg), and the Type II pyrethroid, deltamethrin (6 or 10 mg/kg), were administered daily, 2 hours prior to electrical kindling stimulation. Both pyrethroids facilitated amygdala kindling to a minimal but equivalent degree, but only at dosages that also evoked strong behavioral signs of toxicity. Cismethrin (15 mg/kg, po) produced a 17% reduction in the threshold dosage of ip-PTZ required to induce a seizure, while delaying the onset of generalized seizure activity. Deltamethrin (10 mg/kg, po) failed to alter threshold or latency to seizure onset, but did increase seizure duration. No differences were revealed between po (0,10,15 mg/kg) or ip (0,1,10 mg/kg) administered deltamethrin on thresholds, seizure durations, latencies to myoclonic jerks, or generalized seizure activity following iv-PTZ. (Copyright (c) 1990 by Intox Press, Inc.)