After peripheral noxious stimulation, FKBP51 is upregulated in the dorsal horn following chromatin relaxation. FKBP5 is rapidly epigenetically regulated in the dorsal horn after peripheral noxious stimulation. After complete Freund's adjuvant injection in the ankle joint, we observed an increase in phosphorylation of the transcriptional regulator MeCP2 (1), a decrease in DNA methylation in the promoter sequence of the gene FKBP5 (2) and an increase in FKBP51 protein (3) [34,39]. MeCP2, methyl CpG binding protein 2; HDACs, histone deacetylases; P, phosphorylation. (Online version in colour.)