In particular DNMT 1, 3a, 3b were studied during the development of a neuropathic pain model. Through immunohistochemical analysis it was observed that in the dorsal root ganglion of an adult rat (L4-5) DNMT3B showed an important up-regulation that is observed already 1 week after the induction of the model and that persists for 4 weeks; on the contrary, DNMT1 and DNMT3a showed a moderate and transient up-regulation. Other studies have shown that in a different pattern of pain, acute inflammatory, the expression levels of DNMT3a and DNMT3B are particularly high.