Behavioral evidence for increased acetylcholine receptor sensitivity after nucleus basalis magnocellularis lesions in...

Lesions of the nucleus basalis magnocellularis and the medial septal area have been shown to produce both deficits in memory and decreases in choline acetyltransferase levels. In order to determine whether functional changes in acetylcholine receptor sensitivity also occur, the present experiment examined the ability of acetylcholine, 40 micrograms intraventricularly, to induce motor seizures in nucleus basalis magnocellularis-medial septal area lesioned versus control rats. While choline acetyltransferase activity was only modestly reduced in lesioned rats vs control rats (30%), the seizure scores were considerably higher in lesioned vs. control rats (270%). These results suggest that there is an increased functional response to acetylcholine following bilateral nucleus basalis magnocellularis-medial septal area lesions.