Proconvulsant effects of lindane: Enhancement of amygdaloid kindling in the rat

Rats receiving daily oral administrations of lindane were kindled using daily amygdaloid stimulation. In naive rats, lindane exposure increased the probability of evoking an afterdischarge and increased the probability that a convulsive response would be associated with the afterdischarge. During kindling, lindane increased the rate of acquisition of the fully kindled state. Lindane exposed rats required fewer stimulations, fewer afterdischarges and fewer seconds of afterdischarge to kindle. The final kindled state, however, was not modified by lindane exposure. The effects of lindane on kindling were directly proportional to exposure. A log-linear regression of the data estimated the minimal effective exposure level to be about 0.5 mg/kg/day lindane. Brain concentrations at this exposure were about 0.5 μg/g, while blood levels were near 0.1 μg/ml. The kindled seizure model appears to be a useful tool for estimating exposures at which certain neurotoxic responses emerge.