A Technique for the Study of Acetylcholine Turnover in Mouse Brain in Vivo

Abstract— —A method to measure the rate of acetylcholine turnover in mouse brain in vivo has been developed. It is based on the formation of labelled acetylcholine from intravenously injected labelled choline. The isotopic dilution of choline in the brain has been measured by assaying endogenous choline in the brain by an enzymatic method using tritium‐labelled acetyl‐CoA and purified choline acetyltransferase. The rate of acetylcholine turnover in the brain could be calculated at 50 n‐moles acetylcholine/g/min in conscious mice. In anaesthetized mice and in mice treated with oxotremorine, a decrease of acetylcholine turnover to about 10 n‐moles/g/min was found.