Behavioral Effects of Hippocampal Lesions in Rats With Prior Intraseptal Injection of 6-Hydroxydopamine

Document Type

Article

Publication Date

1-1-1980

Description

Male hooded rats were trained on a schedule of differential reinforcement of low response rates (DRL) until a stable baseline level of responding was obtained. The rats then received a bilateral intraseptal injection of an ascorbic acid solution. They were returned to the DRL schedule for 10 days, after which they received a bilateral intraseptal injection of either the ascorbic acid solution or the vehicle containing 6-hydroxydopamine (6-OHDA). After 10 additional days on the DRL schedule, a bilateral hippocampal ablation was performed on all rats. Performance on the DRL schedule was assessed, and rats that had received 6-OHDA prior to the hippocampal ablation emitted significantly fewer responses under the DRL schedule subsequent to the lesion than those that had received just the vehicle. Fluorescence microscopy reveals a substantial loss of the catecholamines in animals receiving 6-OHDA injections as compared to normals or vehicle-treated rats. The results are discussed within the context of 6-OHDA-induced denervation supersensitivity and the possible disruption of ablation-induced collateral axonal sprouting in the septum.

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