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Selected ion monitoring determination of acetylcholine during methoxypyridoxine seizures
Author(s) -
Suzuki M.,
Nitsch C.,
Wunn W.,
Schmude B.,
Haug P.
Publication year - 1980
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200071117
Subject(s) - acetylcholine , chemistry , choline , convulsant , cholinergic , glutamate decarboxylase , chromatography , propionate , hippocampus , medicine , endocrinology , biochemistry , biology , receptor , enzyme
The neurotransmitter γ‐aminobutyric acid is known to decrease preictally after administration of the potent convulsant methoxypyridoxine, a competitive inhibitor of glutamate decarboxylase. An attempt was made to determine the effect of this γ‐aminobutyric acid decrease on the cholinergic system. Rabbits were immobilized and artificially ventilated in order to avoid hypoxidosis. Seizures were induced by intravenous injection of 100 mg kg −1 methoxypyridoxine; 40 minutes later the animals were decapitated and discrete brain areas removed. Tissue contents of acetylcholine and choline were estimated by gas chromatographic mass spectrometric analysis of the β‐dimethylaminoethyl acetate and propionate derivatives using deuterated internal standards. Gas chromatographic column optimization resulted in a considerable sensitivity gain. Computerized selected ion monitoring was carried out on the dimethylmethyleneimmonium ions using voltage switching. The use of a computer controlled solvent dump valve was implemented to increase precision. No significant difference was observed in the concentration of acetylcholine in the frontal cortex, cerebellar cortex, septum, hippocampus, or caudate of seizure versus control animals; septal choline increased, however. This suggests that the acetylcholine turnover could be increased during seizure.