A simplified enzymatic assay for the determination of acetylcholine and choline in discrete structures of rat brain.

Acetylcholine and choline were determined in discrete structures of the rat brain by using a simplified radioenzymatic method. Animals were killed by microwave irradiation. The time for killing was controlled by estimating the activity of acetylcholine esterase. After extracting acetylcholine and choline from the tissue by formic acid/acetone the amines were separated by thin-layer-chromatography and radioenzymatically labelled as described by SAELENS et al. The radiolabelled acetylcholine was extracted by sodium tetraphenylboron/hexanone. After washing the organic phase with buffer the radiolabelled acetylcholine was measured in a liquid scintillation counter. The contents of acetylcholine and choline were determined in nucleus accumbens septi, olfactory tubercle and striatum and compared with literature data.