Figure 6.

Suppression of PSNL-induced pain behaviors and p38 MAPK phosphorylation by administration of P2Y₁₂ antagonist and AS-ODN. A, B, Administration of the p38 MAPK inhibitor SB203580 reversed mechanical allodynia (A) and thermal hyperalgesia (B) induced by PSNL (^# p < 0.01 compared with vehicle control). C, Western blot analyses with phospho-p38 MAPK, total p38 MAPK, and β-actin antibodies in ipsilateral spinal cord of naive rats and PSNL rats administered with MM-ODN, AS-ODN, vehicle, and MRS2395 (15 μg of total protein loaded). Pretreatment of P2Y₁₂ AS-ODN and antagonist MRS2395 suppressed the activation of p-p38 MAPK but not MM-ODN and vehicle at day 3 after PSNL. D, E, Quantification of Western blot data. The graphs show the level of total p38 MAPK normalized to β-actin (D) and p-p38 MAPK normalized to total p38 MAPK and expressed as a ratio of naive (E). Data represent mean ± SEM (n = 4 each groups; ^# p < 0.01). F–J, IHC shows the expression of phospho-p38 immunoreactivity in the spinal dorsal horn. Tissue sections are from the L5 dorsal horn of a control naive rat (F), 3 d after PSNL administered with intrathecal MM-ODN (G), AS-ODN (H), vehicle (I), and MRS2395 (J). Scale bar, 100 μm. contra, Contralateral; ipsi, ipsilateral.