Sex-dependent differences in the activity and modulation of N -methyl- d -aspartic acid receptors in rat dorsal root ganglia neurons

Abstract Women have greater temporal summation of experimental pain stimuli and also have a higher propensity for developing chronic visceral pain conditions. Sex hormone–mediated regulation of N -methyl- d -aspartic acid receptors (NMDARs) in nociceptive pathways is a plausible mechanism that may underlie these phenomena. The aim of this study was to compare the effect of 17-β-estradiol (E2) in modulation of NMDAR activity in adult male and female rat dorsal root ganglia (DRG) neurons. DRG neurons were collected from adult male or female rats and grown in short-term culture in steroid-free media. NMDAR currents were recorded on small to medium size neurons by whole cell patch clamp using rapid perfusion with saturating concentrations of N -methyl- d -aspartic acid and glycine in the absence of extracellular Mg2+ . We found that the average density of NMDAR currents was 2.8-fold larger in DRG neurons from female rats compared with male rats ( P