The effect of hemicholinium on behavior and on brain acetylcholine and choline in the rat.

Behavior and whole brain acetylcholine and choline levels were studied in rats following intraventricular administration of hemicholinium-3. There was an 80% decrease in the content of acetylcholine after 2 hours. The depletion was associated with a decreased turnover of acetylcholine and aggressive behavior. The acetylcholine level did not return to control values until 72 hours after injection, when hemicholinium was still detectable as determined by fluorescence assay. Endogenous choline levels as determined by microwave fixation were 22.7 +/- 1.1 nmol g-1 and were unaffected by hemicholinium; however, hemicholinium caused a significant reduction in the postmortem increase in choline.