Thermosensitivity of primary sensory neurons in rat dorsal root ganglion

AIM: To study the effects of temperature on medium-diameter primary sensory neurons in rat dorsal root ganglion (DRG). METHODS: Whole-cell patch-clamp recording was performed on medium-diameter DRG neurons freshly isolated from rats for observing the firing characteristics by temperature gradient stimulation. RESULTS: According to the firing characteristics of the primary sensory medium neurons to the temperature changes in rat DRG, there were 2 classes of cells: In class Ⅰ, the medium neuron was temperature-sensitive neuron. All-or-none action potentials could be generated and the number of spikes and the frequency decreased with increase of the temperature, and vice versa. The cold-sensitive neuron was voltage dependent. In class Ⅱ, the medium neuron was temperature-insensitive neuron. It only had single action potential with increase or decrease of the temperature, and the amplitude of the single action potential decreased with increase of the temperature. CONCLUSION: The two classes of rat DRG medium neurons have different thermosensitivity.