Changes in acetylcholine in caudate nucleus tissue isolated in situ detected by gas chromatography mass spectrometry selected ion monitoring.
Acetylcholine neurons in the striatum are believed to be primarily intrinsic. In cats a cylinder of caudate tissue was isolated unilaterally from all afferent and efferent connections while preserving the blood supply through the base of the cylinder. Cats were decapitated two and four weeks after operation. Dorsal, intermediate and ventral portions of the viable isolated cylinder, and corresponding tissue from the contralateral hemisphere serving as control, were removed, weighed and frozen. Deuterated internal standards at concentrations approximating those of acetylcholine and choline in the tissue were added and acetylcholine and choline extracted, reacted with propionyl chloride and demethylated with sodium benzenethiolate. The derivatives were separated by gas chromatography, and the acetylcholine and choline concentrations in the tissue evaluated using selected ion monitoring of m/z 58, 60 and 64. The observed decrease in the acetylcholine concentration in the dorsal portion could be due either to the interruption of the cholinergic thalamic input or to the more severe ischemia in this portion. The increase in the acetylcholine concentration in the ventral portion, where blood circulation is normal, may reflect accumulation of acetylcholine in inactive intrinsic neurons after severance of their input, or indicate sprouting of intrinsic acetylcholine neurons.
D000109:Acetylcholine / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D001711:Biotransformation; D002415:Cats; D002421:Caudate Nucleus / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008297:Male; D013997:Time Factors
D000109:Acetylcholine