KINETICS OF [3H]ACETYLCHOLINE SYNTHESIS AND RELEASE IN PRIMARY CELL CULTURES FROM MAMMALIAN CNS

— The present study was undertaken to characterize the cholinergic system of primary cell cultures of mouse and rat CNS. In confirmation of previous reports, primary cultures were found to contain choline acetyltransferase (ChAc). Furthermore they contain acetylcholine (ACh) as measured by two different bioassays. They also synthesize [3H]ACh from [3H]Choline offered to the cultures. The formation of [3H]ACh is inhibited in the presence of hemicholinium-3 (10−6m) to 50% or ouabain (10−3m) to 20% of the values found in untreated cultures. Omission of Na + from the incubation solution also diminishes the [3H]ACh formation of the cells. [3H]ACh is released upon depolarisation by K+ ions in a concentration dependent manner. The release can be prevented by lack of Ca2+ ions in the incubation solution.