Suppressive effects of low-power laser irradiation on bradykinin evoked action potentials in cultured murine dorsal root ganglion cells.

The effects of Ga-Al-As diode laser (830 nm, 16.2 mW) irradiation on the distal portion of the processes of cultured murine dorsal root ganglion (DRG) neurons associated with C-fibers were studied by patch-clamp whole-cell recording of membrane potentials at the cell body. The chemical as well as laser light stimulations were limited to the processes of the neuron isolated from the cell body with a separator. The action potentials elicited by bradykinin (BK) in the cell body were reversibly suppressed by the irradiation of laser light. The laser irradiation may block the conduction of nociceptive signals in primary afferent neurons. The present experimental method offers a simple and easy to use procedure for studying the pain relief effects by laser irradiation.