Membrane Lipid Changes in Organic Solvent Tolerant Neural Cells

Although, organic solvents are known to interact with neural membranes and to possess acute anesthetic properties, very little is known about the chronic effects of organic solvents on neural membranes. In the present study lipid compositional changes were examined after chronic exposure to the chlorinated organic solvents, trichloroethylene (TCE) and perchloroethylene (PCE). Animals were exposed continuously in inhalation chambers. Each experimental group had its own control group exposed simultaneously to air under identical conditions. Exposure to these organic solvents had only minor effects on lipid class composition. A tendency towards a decreased cholesterol to phospholipid ratio was observed, whereas the content of cerebro-sides was unaffected. However, the proportions of the polyunsaturated fatty acids of ethanolaminephosphoglyceride (EPG) was consistently changed after exposure to either of these solvents for three months at (320 ppm). After longer exposure periods such alterations were observed at even lower solvent concentrations. This change in fatty acid pattern was characterized by an increase in linoleic acid derived fatty acids, with a concominant decrease in fatty acids of the linolenic acid family. These changes may be an effort to compensate for the increased hydrophobic volume of membranes induced by dissolved solvent molecules. This compensation could be achieved by insertion of less coned lipid components into the membrane. The observed decrease in cholesterol to phospholipid ratio and the increase in the less saturated linoleic acid derived fatty acids could serve this function. Another possibility could be that chlorinated organic solvents interfere with the protein structure of desaturases, resulting in an alteration in the speed of desaturation and a changed fatty acid composition.