ON THE ORIGIN OF THE ACETYL MOIETY OF ACETYLCHOLINE IN BRAIN STUDIED WITH A DIFFERENTIAL LABELLING TECHNIQUE USING ³H‐¹⁴C‐MIXED LABELLED GLUCOSE AND ACETATE

Abstract

Abstract —Cortex slices of rat brain were incubated with glucose mixed‐labelled with 3 H and 14 C in the 6‐position and the 3 H/ 14 C ratios of lactate, acetate, citrate and acetylcholine were determined. The values obtained were: lactate 0·95, acetate 0·85, citrate 0·65 and acetylcholine 0·67 when expressed in relation to a glucose 3 H/ 14 C ratio of 1·00. When brain slices were incubated with [2‐ 14 C, 2‐ 3 H]acetate in the presence of unlabelled glucose, labelled acetylcholine was formed with a 3 H/ 14 C ratio not significantly different from the labelled substrate. The results indicate that citrate is a precursor to the acetyl moiety of acetylcholine.