17h-estradiol attenuates a, h-meATP-induced currents in rat dorsal root ganglion neurons

The effects of 17h-estradiol on the a,h-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 a,h-me ATP in acutely dissociated DRG neurons. When neurons were pre-incubated with 17h-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, 17h-estradiol did not have any significant effect on the sustained current evoked by a,hmeATP. The inhibitory effects were concentration-dependent, reversible and could be blocked by the estradiol receptor inhibitor, ICI 182,780 (1 AM). However, bovine serum albumin-conjugated 17h-estradiol (17h-estradiolBSA, 10nM) failed to mimic the effects of 17h-estradiol. 17a-estradiol, the inactive isoform, did not have significant effects on ah-meATP-induced currents, either. Sustained currents induced by ATP (100 AM) in nodose ganglion (NG), superior cervical ganglion (SCG) and otic ganglion (OTG) neurons were not affected by 17hestradiol. These results suggest that the female gonadal hormone, 17h-estradiol, might participate in control of pain by modulating P2X3 receptor-mediated events in sensory neurons. D 2005 Elsevier Inc. All rights reserved.