Behavioral and monoaminergic changes after lindane exposure in developing rats

The effects of lindane on behavior and central monoaminergic systems were studied in rat pups at 15 days of postnatal age. Pups were previously given nonconvulsant lindane PO doses, either a single 20 mg/kg or 7-day repeated 10 mg/kg doses. Both treatment schedules improved the passive avoidance acquisition but only the acute administration prolonged the step-through latency. Acute lindane decreased the motor activity, whereas the repeated dosing increased it. Increases of the ratio 5-HIAA/serotonin in several brain regions and of the ratio DOPAC/dopamine in the mesencephalon after a single dose of lindane suggest an enhanced monoaminergic turnover. In contrast, repeated lindane doses decreased monoamine/metabolite ratios excluding the striatum, where an increase of DOPAC/dopamine ratio correlates with the higher motor activity of these animals. It is postulated that both the imbalance of the central monoaminergic systems and the lindane-induced GABAergic blockade may be the basis of the behavioral alterations. (C) 1998 Elsevier Science Inc.