The Absence of ‘Surplus’ Acetylcholine Formation in Prisms Prepared From Rat Cerebral Cortex

Prisms of rat cerebral cortex incubated without cholinesterase inhibitor showed an increase in ACh content during the first hour of incubation. The effects of adding cholinesterase inhibitors during the second hour depended on the potassium concentration. At 6 mM‐K+ there was only a small rise in ACh but when K+ was raised to 25 mM a large increase in ACh content was observed. It is proposed that the increase in ACh is due to the reuptake of released ACh.