Calcium signaling in cold cells studied in cultured dorsal root ganglion neurons

Abstract

Thermosensitive cold cells were identified in cultured dorsal root ganglion neurons from newborn rats. The neurons were loaded with a calcium indicator, Fura-PE3, and the change in intracellular Ca 2+ concentration ([Ca 2+] i) of the neurons was measured with microfluorimetry. Thirteen per cent of the cells responded to the cold stimulation. The diameter of the responder cells was 16.3±3.2 μm (mean±S.D., n=25). The lowering of the temperature from 35°C to 20°C increased [Ca 2+] i from 59.6±10.6 nM to 203.4±14.8 nM ( n=25). The [Ca 2+] i response was dependent on the intensity of the cold stimulation. The depletion of extracellular Ca 2+ diminished the Ca 2+ elevation. However, a Na +-free condition did not influence the response. We concluded that the cold stimulation opens Ca 2+-permeable channels in putative cold cells from dorsal root ganglion neurons.