Objective: To investigate the effects of cinnamaldehyde on Ca2+ concentration change in dorsal root ganglia cells of rats with 0℃ cold stress

and mRNA expressions of transient receptor potential cation channel

subfamily A

member 1 (TRPA1) and transient receptor potential cation channel

subfamily M

member 8 (TRPM8). Method: The rat dorsal root ganglion neuron cells were put in 0℃ cold stress to detect the activity of cells under the different time length of cold stress by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. Cinnamonaldehyde was added to detect the changes in intracellular Ca2+ distribution by the laser confocal microscopy. Furthermore

Real-time PCR method was used to measure the mRNA expression of TRPA1 and TRPM8. Result: There was no significant difference in cell viability under the different time length of cold stress. Cold stress decreased cytosolic Ca2+ concentration within dorsal root ganglia (DRG) neurons (P<0.05)

while a certain amount of cinnamicaldehyde could make it significantly rise (P<0.01). Real-time PCR method showed that under long-time old stress

the mRNA expression of TRPA1 was up-regulated (P<0.05). And the TRPM8 mRNA expression under long-time cold stress was clearly higher than that under short-time cold stress (P<0.05). Cinnamaldehyde at the appropriate concentration can up-regulate the TRPA1 mRNA expression of rat DRG neurons under cold stress (P < 0.05

P < 0.01). The effect of cinnamaldehyde on TRPM8 was unclear yet. Conclusion: The cold stress can impact TRPA1 and TRPM8

and decrease the cytosolic Ca2+ concentration. Its action mechanism is to activate TRPA1 channel and them increase the cytosolic Ca2+ concentration.