Intracellular study of substance P in human Scarpa's ganglion cells

The effect of substance P on surgically removed human Scarpa's ganglion cells was investigated by intracellular recordings and bath application under in vitro conditions. The neuropeptide produced a slow depolarization of the membrane potential which was accompanied by an increase in membrane resistance. Furthermore, an enhanced firing in response to depolarization occurred. The results strongly support a modulatory action of the neuroactive peptide substance P on human Scarpa's ganglion cells.