Deficit in active avoidance learning in rats following penicillin injection into hippocampus

Abstract

Penicillin was found to cause epileptiform (spike) activity when injected into the hippocampus of male rats. Animals so prepared were found to be severely impaired in the acquisition of a two-way active avoidance task. Animals with bilateral hippocampal destruction produced by aspiration and animals receiving an antibiotic, sodium sulfadiazine, which did not cause epileptiform activity learned the task as quickly as did unoperated animals. In a second study, rats were trained on the two-way task and then subjected to penicillin injection. They rapidly reached the pre-operative criterion showing significant amounts of retention. The fact that they were able to perform the avoidance response quite readily suggested that the impaired animals in Experiment 1 were not suffering from some basic sensory or motor loss.