PTGS2 and endometriosis: EP2, Cox-1, Scn11a and Trpv1 mRNA concentrations were significantly increased in dorsal root ganglia (DRG; clusters of cell bodies of afferent sensory neurons that transmit noxious stimuli from the periphery to the spinal cord) from endometriosis mice (p < 0.05; Fig. 2a–d); EP4 and Cox-2 were unchanged (Supplementary Fig. 3c,d).