Central cholinergic correlates of low dose ethanol-induced locomotor stimulation.

Brain area levels of acetycholine and choline plus the turnover rate of acetylcholine were measured in three strains of rats given low, locomotor-stimulating doses of ethanol. Maudsley reactive (MR/N), Sprague-Dawley, and randomly bred MR/N (MRrb) rats were killed by microwave irradiation and cholinergic function was measured by gas chromatography/mass spectroscopy methods. The results show that the MR/N strain (2 and 5 months old), which elicits enhanced locomotor stimulation after low doses of ethanol, also demonstrates significant increases in cholinergic function at the time of behavioral stimulation. However, after locomotor stimulation, cholinergic parameters returned to normal in these animals. Strains which do not show enhanced locomotor activity after ethanol did not demonstrate significant central cholinergic changes. We conclude that central cholinergic function is related to behavioral stimulation elicited by low doses of ethanol in the MR/N rat strain but not other strains.