The brain ethanol binding potential and its effect on the ethanol

Introduction In vivo magnetic resonance spectroscopy (MRS) can provide a direct quantitative measure of brain ethanol following its systemic administration [1]. Through this approach, it has been reported that the amplitude of the methyl H resonance relates to tolerance to ethanol’s intoxicating effects. Specifically, ethanol tolerance is associated with increased MRS signal intensity per unit brain ethanol concentration [2]. It has been suggested that ethanol MRS amplitude could vary with tolerance through changes in the methyl H T2 value [3], however no biophysical mechanism linking ethanol pharmacology to ethanol methyl H spin relaxation has been described. Herein, a relationship between the ethanol brain binding potential (BP) and methyl H T2 value is proposed based on the assumption that brain ethanol exchanges rapidly between macromolecule-bound and unbound states. Experimental support for the proposed relationship is provided from MRS measurements following intravenous (I.V.) administration of varying quantities of ethanol in four ethanol-naïve rhesus macaques.