Optical stimulation in mice lacking the TRPV1 channel

Lasers can be used to stimulate neural tissue, including the sciatic nerve or auditory neurons. Wells and coworkers suggested that neural tissue is likely stimulated by heat.[1,2] Ion channels that can be activated by heat are the TRPV channels, a subfamily of the Transient Receptor Potential (TRP) ion channels. TRPV channels are nonselective cation channels found in sensory neurons involved in nociception. In addition to various chemicals, TRPV channels can also be thermally stimulated. The activation temperature for the different TRPV channels varies and is 43°C for TRPV1 and 39°C for TRPV3. By performing an immunohistochemical staining procedure on frozen 20 μ m cochlear slices using a primary TRPV1 antibody, we observed specific immunostaining of the spiral ganglion cells. Here we show that in mice that lack the gene for the TRPV1 channel optical radiation cannot evoke action potentials on the auditory nerve.