Convulsive properties of lindane, lindane metabolites, and the lindane isomer alpha-hexachlorocyclohexane: effects on the convulsive threshold for pentylenetetrazol and the brain content of gamma-aminobutyric acid (GABA) in the mouse.

The threshold for pentylenetetrazol-induced convulsions in the mouse is affected by lindane in two opposite ways. Following the administration of a single dose of lindane, the threshold first decreases and then, after 2 days, increases above the normal level. None of the tested metabolites of lindane altered the convulsive threshold. When lindane elevates the convulsive threshold it also elevates the content of γ-aminobutyric acid (GABA) in the brain. The lindane isomer α-hexachlorocyclohexane elevates both convulsive threshold and the GABA content. The smallest single oral dose of lindane lowering the convulsive threshold for pentylenetetrazol in the mouse, 3 hr after administration, corresponds to a lindane concentration of 56 ppb in whole blood.