Enhanced Binding of Chlorpromazine to Cholesterol-Depleted Synaptosome Fractions

Abstract

Brain synaptosome fractions were treated by Murphy's method in order to deplete the membrane cholesterol. The binding of ³⁵S-chlorpromazine to these treated membranes was measured. It was found that the membrane/buffer partition coefficient of the drug was threefold greater in the treated synaptosome-rich fractions compared with the untreated fractions. The results suggest that cholesterol may not be a part of the membrane hydrophobic binding site for tranquilizers.