CHOLINERGIC MECHANISM IN THE CEREBRAL CORTEX—A FURTHER STUDY WITH ACETYL-β-METHYLCHOLINE (METHACHOLINE)

Abstract

In rats anaesthetized with pentobarbitone, somatosensory evoked potentials produced by stimulation of the contralateral or the ipsilateral forepaw were used as a measure of activity in different neuronal population. Drugs were applied to the pial surface by using cortical-cup technique and changes were measured in the somatosensory evoked responses. Cortical application of acetylcholine and acetyl-β-methylcholine increased the amplitude of the repetitive after discharges. No significant effect was seen on the primary complex. The effect of cholinomimetic drugs was blocked by benactyzine. It is suggested that the afferent pathways responsible for the repetitive after discharges involve a cholinergic mechanism.