On the sensitivity of intact cells to perturbation by ethanol

A comparison was made of ethanol's effects on the order of plasma membranes in intact cells and some isolated membrane preparations. Order was assessed by steady-state fluorescence polarization techniques using the non-permeant probe, TMA-DPH. The data show that two cultured cells, rat neonatal astroglial and N2A neuroblastoma, were sensitive to significant ethanol-induced disordering within the anesthetically relevant range (100 - 200 mM). Human erythrocytes, cultured fibroblasts and homogenized astroglial cells required higher ethanol concentrations (greater than 250 mM) to produce a similar effect. Intact erythrocytes were approximately twice as sensitive as erythrocyte ghost membranes to ethanol-induced perturbation. The neonatal glial and N2A cells were approximately five times more sensitive than synaptic membranes to ethanol effects. DMPC and DMPC + cholesterol liposomes and myelin membranes were insensitive to ethanol's effects. The incorporation of 10 mole % ganglioside GM1 sensitized the liposomes to ethanol-induced perturbation.