Effect of limbic system lesions on acetylcholine release from the cerebral cortex of the rat.

Abstract

The effect of electrocoagulative lesions placed in the septum, fornix and fimbria, fimbria and hippocampus on ACh release from the cerebral cortex was investigated in rats under urethane anaesthesia. At least 2 weeks elapsed between the stereotactic placement of the lesions and the determination of ACh output. ACh was determined by bioassay on the dorsal muscle of the leech. No lesion affected the spontaneous release of ACh. The increase in ACh output induced by i.p. administration of amphetamine was abolished by the septal lesion only. On the other hand, the increase in ACh output induced by i.p. administration of scopolamine was strongly reduced by lesions of the septum, of the fornix and fimbria and to a lesser extent of the fimbria. The administration of amphetamine and scopolamine discloses therefore a specific functional impairment of the cerebral cholinergic mechanisms in rats with limbic lesions.