sentences:  Detection of glutamate by the GPCR Metabotropic glutamate receptor 6 results in closing of the TRPM1 channel.At the onset of light, glutamate release is halted and mGluR6 is deactivated; this results in opening of the TRPM1 channel, influx of sodium and calcium, and depolarization of the bipolar cell.In addition to the retina, TRPM1 is also expressed in melanocytes, which are melanin-producing cells in the skin.