A NOTE ON THE CHEMICAL MECHANISM OF THE NAUTA-GYGAX TECHNIQUE

This research attempts to determine which chemical groups are involved in Nauta impregnation of degenerating peripheral and optic nerve fibers. Before the Nauta-Gygax technique, tissues either were treated with bromine water to block unsaturated bonds or with acetone or chloroform-methanol to extract various lipid constituents. Bromination completely suppressed Nauta impregnation of degenerating optic and sciatic nerve fibers. This, together with data provided by extracted preparations, implicates unsaturated lipids, probably cholesterol esters, in the impregnation. The basic similarity in chemical mechanism of the Nauta and Marchi impregnations of degenerating fibers is discussed. Whereas the Marchi reaction in nerve fibers is limited to degenerating myelin, data are presented indicating that Nauta impregnation involves both degenerating myelin sheath and axis cylinder.