J Huazhong U Sci Med
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J Huazhong U Sci Med · Apr 2012
Inhibition of glial activation in rostral ventromedial medulla attenuates mechanical allodynia in a rat model of cancer-induced bone pain.
Descending nociceptive modulation from the supraspinal structures plays an important role in cancer-induced bone pain (CIBP). Rostral ventromedial medulla (RVM) is a critical component of descending nociceptive facilitation circuitry, but so far the mechanisms are poorly known. In this study, we investigated the role of RVM glial activation in the descending nociceptive facilitation circuitry in a CIBP rat model. ⋯ RVM microinjection of p38 MAPK inhibitor (SB203580) abolished the activation of microglia, reversed the associated up-regulation of pro-inflammatory mediators and significantly attenuated mechanical allodynia. Taken together, these results suggest that RVM glial activation is involved in the pathogenesis of CIBP. RVM microglial p38 MAPK signaling pathway is activated and leads to the release of downstream pro-inflammatory mediators, which contribute to the descending facilitation of CIBP.