抄録
We have reported that the extensor digitorum longus muscle (EDL) of rat 2 days after lengthening contraction (LC) is mechanically hyperalgesic (delayed onset muscle soreness, DOMS) (Taguchi et al, J Physiol 564) and that the C-fiber receptors of this hyperalgesic muscle increased their sensitivity to mechanical stimulation (Taguchi et al, J Neurophysiol 94). The mechanism for this increased sensitivity to mechanical stimulation has not been known yet. In the present study, we used PCR-based cDNA subtraction method, "suppression subtractive hybridization" procedures to define genes upregulated in dorsal root ganglion cell (DRG) of SD rat with DOMS. LC of the right EDL was induced by electrical stimulation of the common peroneal nerve while the muscle was being stretched. The right DRGs (L3-L4) were dissected in the control group and 2 days after LC in the DOMS group. Using the cDNA subtraction method, we detected 65 different genes upregulated. Among these 65 genes were annexin A2 and calbindin 1, which were recently reported to be involved in nociception. We quantified expression levels of these 2 genes in DRGs form the DOMS group and the control group using quantitative PCR assay. Expression levels of these two genes relative to an internal standard (glyceraldehyde-3-phosphate dehydrogenase) were significantly increased in the DOMS group compared to the control group (p<0.05, n=5 each). This is the first demonstration that annexin A2 and calbindin 1 were upregulated in DRG from rat with DOMS. [J Physiol Sci. 2008;58 Suppl:S163]
