Mechanical transduction by rat dorsal root ganglion neurons in vitro

Although it is generally presumed that mechanical sensitivity of somatosensory nerve fibers results from the activation of mechanosensitive ion channels, a mechanically-gated whole-cell current has never been demonstrated in dorsal root ganglion (DRG) neurons, We performed patch clamp experiments on rat DRG neurons in culture, and report the first mechanically-activated current in somatosensory neurons (I-mech) This whole-cell current is observed in most dorsal root ganglion neurons but not in non-sensory sympathetic ganglion neurons. The current-voltage relation of I-mech indicates that it is a non-selective cation current. Sensitivity of I-mech to block by gadolinium suggests that it may be mediated by a member of a family of mechanosensitive non-selective cation channels observed in many cell types. Sensitivity to benzamil supports this idea, and further suggests that the current might be mediated by a member of the degenerin/epithelial sodium channel (DEG/ENaC) family. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.