Effect of organic solvents on human erythrocyte membrane acetylcholinesterase activity in vitro.

To study the effects of aromatic hydrocarbons, chlorinated aliphatic hydrocarbons, and alcohols on erythrocyte membrane, changes in the membrane-bound acetylcholinesterase (AchE) activity were tested after solvent treatment by the Ellman method. When the maximal effects of these solvents were tested at +37 degrees C, they diminished the AchE activity: benzene 75%, xylene 65%, styrene 80%, trichloroethylene 55%, tetrachloroethylene 60%, 1,1,1-trichloroethane 25%, and 1,1,2,2-tetrachloroethane 75%. Of the alcohols studied, only ethanol had a slight AchE inhibiting effect at +37 degrees C. The decrease in the incubation temperature increased the AchE inhibiting potency of aromatic hydrocarbons more than that of chlorinated aliphatic hydrocarbons and alcohols. The differences in inhibition may be due to the lipid solubility of the solvents, but also other factors, e.g. molecular structure, may determine it. Changes in the membrane-bound AchE may be one of the factors determining membrane fluidity.