Dilute ethyl alcohol: effect on the sciatic nerve of the mouse.

The histological changes produced in peripheral nerve by topical ethyl alcohol have been infrequently studied in spite of widespread use of this neurotoxic agent in the management of pain and spasticity. In the present study the sciatic nerves of a series of albino mice were exposed to ethanol in concentrations of from 10% to 50% for from 15 to 60 seconds. An immediate physiochemical reaction took place, resulting in splitting of myelin sheaths and swelling of cellular organelles and cytoplasm. Nerves subsequently underwent Wallerian degeneration. A central core of fibers appeared to be normal. The longer exposure times or higher alcohol concentrations increased the extent to which the peripheral rim of altered tissue extended centrally into the nerve. Within altered tissue, all fiber types and sizes were found to be affected to an equal degree. To study the physical properties of alcohol in solution, absolute alcohol was slowly placed at the bottom of a cylinder filled with artificial or normal human spinal fluid and sequential levels of the solution were sampled 30 and 60 seconds after injection. Though hypobaric, alcohol dispersed rapidly so that specimens taken from the bottom of the cylinder were 65% as concentrated as specimens taken from the surface.