17beta-estradiol Attenuates Alpha, Beta-meATP-induced Currents in Rat Dorsal Root Ganglion Neurons

The effects of 17beta-estradiol on the alpha,beta-me ATP-induced currents were studied on dorsal root ganglion (DRG) neurons using whole-cell recording technique. Three types of currents (transient, sustained or biphasic) were evoked by alpha,beta-me ATP in acutely dissociated DRG neurons. When neurons were pre-incubated with 17beta-estradiol (10-1000 nM) for 4 min, an inhibition of the transient current and the transient component of the biphasic current was observed. In contrast, 17beta-estradiol did not have any significant effect on the sustained current evoked by alpha,beta-meATP. The inhibitory effects were concentration-dependent, reversible and could be blocked by the estradiol receptor inhibitor, ICI 182,780 (1 microM). However, bovine serum albumin-conjugated 17beta-estradiol (17beta-estradiol-BSA, 10 nM) failed to mimic the effects of 17beta-estradiol. 17alpha-estradiol, the inactive isoform, did not have significant effects on alphabeta-meATP-induced currents, either. Sustained currents induced by ATP (100 microM) in nodose ganglion (NG), superior cervical ganglion (SCG) and otic ganglion (OTG) neurons were not affected by 17beta-estradiol. These results suggest that the female gonadal hormone, 17beta-estradiol, might participate in control of pain by modulating P2X3 receptor-mediated events in sensory neurons.