Excitotoxin lesion of nucleus basalis causes a specific decrease in Go mRNA in cerebral cortex

Abstract
Lesions of the ascending cholinergic pathway from nucleus basalis are known to have profound effects on cortical function. In particular, a substantial potentiation of carbachol‐stimulated polyphosphoinositide turnover is detected from 1 day after lesion and is maintained for several days before returning to normal by 1 month. In this study the effect of this lesion was investigated on levels of three G‐protein α‐subunit mRNAs. Excitotoxin lesion of the nucleus basalis caused a selective reduction in the levels of Goα mRNA in cerebral cortex ipsilateral to the lesion, G5α and Giα mRNA being unaffected. The maximal effect was obtained at 3 days after lesion where levels of Goα mRNA were decreased by 40% compared to sham‐operated animals. Levels of Goα mRNA returned to normal values by 28 days. Treatment with MK‐801 caused a significant attenuation of the decrease in Goα mRNA, indicating the involvement of NMDA receptors in this response.