Fig. 4. Nerve conduction blockade prevents p38 activation in spinal microglia. Immunofluorescence shows phospho-p38 (p-p38) immunoreactivity in the spared nerve injury (SNI) rats (  A ) and SNI rats receiving nerve blockade (  B ).  Scale , 20 μm. (  C ) Number of p-p38–immunoreactive cells in the medial superficial (laminae I–III) spinal cord with pretreatment of bupivacaine microspheres. **  P < 0.01, compared with sham controls; ##  P < 0.01, compared with SNI, analysis of variance; n = 4. Sham control rats were given vehicle (fibrin solution of microspheres). SNI rats were given vehicle before SNI. Bupivacaine microspheres were applied before SNI.