Sigma-1 receptor-mediated increase in spinal p38 MAPK phosphorylation leads to the induction of mechanical allodynia in mice and neuropathic rats

► Spinal Sigma 1 receptor activation increased p38 MAPK phosphorylation. ► Inhibition of p38 MAPK attenuated PRE084-induced MA, but not TH. ► In CCI rats, early blockade of Sigma 1 receptor reduced p38 MAPK phosphorylation. ► p38 MAPK was responsible for induction of CCI-induced MA, but not TH. ► P38 MAPK was not related with maintenance of CCI-induced MA or TH.