Analysis of spinal cord Mapk8 expression in supplemental strains. In these experiments both real time qPCR and Western analysis were used to quantify mRNA and protein levels respectively. Graph A contains the results of qPCR experiments in which the relative levels of Mapk8 mRNA for high late phase responding strains were compared with low responding ones. In graph B, similar experiments were performed using spinal cord protein homogenates. For the protein experiments the spinal cord levels of JNK1 were normalized to the spinal cord levels in the intermediate-responding BALB/c mice arbitrarily set at a level of 1.0. For all experiments samples from n = 4 mice per strain were analyzed in triplicate. Bars represent mean ± S.E.M. Three strains within each group were compared to other strain group, *p < 0.05.