BRAIN ALCOHOL DETECTABILITY INCREASE WITH REPEATED ADMINISTRATION IN HUMANS - A PROTON SPECTROSCOPY STUDY

Proton MRS was used to detect brain alcohol after repeated alcohol exp osure in human subjects, MRS detectability measurements were made afte r administration of an alcoholic drink (0.6 g/kg alcohol) and after an identical drink administered 6 h later. Between-drink differences in the methyl proton triplet resonance of ethyl alcohol were assessed at statistically equivalent and near-peak blood alcohol concentrations (r eflecting brain alcohol concentrations) and statistically equivalent i nternal standard N-acetyl resonance areas after Drinks 1 and 2, respec tively, Brain alcohol detectability was not altered in TE 30-ms spectr a but was increased in all five subjects after Drink 2 by an average o f 70% in TE 270-ms spectra (P < 0.01), This was accompanied by signifi cant between-drink differences in subjective ratings of alcohol's effe cts, suggestive of induction of acute alcohol tolerance, These finding s suggest increased brain alcohol detectability in TE 270-ms spectra a fter repeated alcohol exposure that may reflect acute alcohol toleranc e.