Figure 4
Activation of p38 is critical in the S1P induced I CAPS potentiation in sensory neurons. A, In a typical current recording of a nociceptor, the ICAPS increase caused by 1.0 μM S1P stimulation is greatly diminished by inhibition of p38 activation by SB203850 (1.0 μM). Zero current is drawn as dashed line. B, Pretreatment of sensory DRG neurons with SB203850 (1.0 μM) significantly reduced the S1P mediated potentiation of ICAPS. ***p < 0.001, **p < 0.01, MWU-test. C, Western blot analysis of p38 activation (p-p38) showed that S1P significantly increased the p-p38 levels in sensory neurons, whereas SB23850 (SB) reversed the p-p38 levels to control, unstimulated levels. ***p < 0.001, **p < 0.01, ANOVA on Ranks followed by Tukey post-hoc test, numbers within the bars represent the number of individual cells recorded.