ISSN:
1432-1912
Keywords:
Synaptic transmission
;
14C-choline
;
Acetylcholine
;
Phosphatidylcholine
;
Urethane anesthesia
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Concentrations and specific radioactivities of choline, acetylcholine, phosphorylcholine, lipid choline, and sn-glycero-3-phosphorylcholine after i.v. injection of methyl-14C-choline were measured in the brain of untreated controls and of rats anesthesized with urethane. The specific activity was found to be decreased during deep anesthesia by 40% in acetylcholine, 20–30% in phosphorylcholine, 50–75% in lipid choline, and 30–40% in sn-glycero-3-phosphorylcholine. No significant change was detected in the specific activity of choline. The brain concentration of acetylcholine was increased by 40%, the concentration of sn-glycero-3-phosphorylcholine, however, was diminished by 10% during anesthesia. No change was found in the concentration of the other choline containing compounds investigated. Measuring choline incorporation into 4 subcellular fractions of brain tissue specific activities were found to be decreased by the same percentage, although 2 fractions (nuclei and microsomes) were higher labelled than the 2 other fractions (crude mitochondria with synaptosomes and lysosomes). A correlation between the biochemical and the functional alterations is supported by the dose-effect relationships on both parameters. It is suggested that urethane reduces turnover of lipids and by that mechanism inhibits the exocytotic release of the transmitter from presynaptic nerve endings.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00500888
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