S100, a brain-specific protein: Localization and possible role in the snail nervous system

Abstract

Immunofluorescence techniques were used to show that S100 is present on the surface of neuronal and glial membranes of Helix pomatia in vitro. By the method of rocket immunoelectrophoresis of aqueous, Trition, and n-pentanol extracts of snail nervous tissue, S100 was demonstrated to be mainly in the membrane fraction. Anti-S100 antiserum inhibited the electrical activity of identified neurons, pointing to a relationship of this protein with ionic channels of the excitable membrane. The effect of anti-S100 antiserum on the membrane was potential dependent and controlled by the Ca²⁺ concentration.