Figure 2.

NA neurons isolated from injured rats exhibit complex responses to MIF. A, Effects of different doses of MIF (15-60 min pretreatment) on the incidence of NA neurons with OA when isolated 3-5 months after sham surgery. OA was measured at RMP and when artificially depolarized to −45 mV. Comparisons of OA at each concentration versus vehicle treatment (0 ng/ml) were performed with Fisher's exact test (p < 0.025 considered significant after Bonferroni correction for 2 comparisons). B, Effects of MIF on the incidence of neurons with OA 1-4 months after SCI surgery (p < 0.017 considered significant after Bonferroni correction for 3 comparisons). C, Representative recording at RMP of a hyperactive NA neuron isolated from an SCI rat and exposed to MIF starting at t = 0. D, Effect of MIF exposure on mean membrane potential at different time points (n = 11). Comparison between control period (t = −10 s) with subsequent time points was performed with Friedman test followed by Dunn's multiple comparisons test. Data are mean ± SEM. E, Effect of MIF exposure on AP firing frequency measured by 20 s time bins (n = 11). Comparison between control period (−20: 0 s) with subsequent time bins was performed with Friedman test followed by Dunn's multiple comparisons test. Each circle represents 1 neuron. Bars represent medians. MP, Membrane potential.