Low doses of muscimol produce anticonflict actions in the lateral septum of the rat.

Muscimol microinjected into the lateral septum of the rat produced a dose dependent increase in punished responding over the dose range of 100 pg-5 ng. The higher doses used (10 ng and 1 microgram) produced sedation and ataxia, markedly reducing the number of approaches to the water spout. This steep, biphasic dose response curve for the anticonflict actions of muscimol may explain contradictory findings in the literature concerning GABAergic involvement in the anxiolytic actions of benzodiazepines. The low dose of muscimol needed to produce a significant anticonflict effect in the lateral septum suggests that this nucleus may be a critical site in anxiety-related behaviors.