IMMUNOHISTOCHEMICAL AND ELECTROPHYSIOLOGICAL DEMONSTRATION OF SUBSTANCE-P IN HUMAN VESTIBULAR GANGLION-CELLS

This study was performed in order to determine the immunohistochemical expression and distribution pattern as well as the electrophysiologic al actions of substance P in human vestibular ganglion cells. Substanc e P-like immunostaining was mainly found in the cytoplasm of small ves tibular ganglion cells. In contrast, nerve fibers were not labelled. U sing intracellular recording techniques, substance P produced a slow d epolarization of membrane potentials accompanied by an increase in mem brane resistance. Furthermore, an enhanced firing response to depolari zation occurred.