Yu Li-hua, Li Na, Liu Cai-yue, Ma Bei
Department of Physiology, The Key Laboratory of Molecular Neurobiology, Ministry of Education, Second Military Medical University, Shanghai, P.R.China.
Neuro Endocrinol Lett. 2011;32(6):811-5.
P2X3 receptors are expressed in trigeminal ganglia (TG) and participate in the transduction of facial pain. However, the mechanisms underlying P2X receptor-mediated nociception at different estrogen levels has not been examined.
In this study, female rats were randomly divided into sham-operated (sham), ovariectomized (OVX), and estrogen-treated groups. In each group, the facial mechanical pain threshold was tested and the TG were harvested for a real-time PCR analysis of P2X3 receptor mRNA and western blot analysis of protein level.
In OVX rats we found that the mechanical pain threshold was significantly decreased compared with that in sham rats. Estrogen replacement reversed the decrease. The expression of P2X3 mRNA level in TG from OVX rats was significantly increased, consistent with the enhanced P2X3 receptor in protein level. Estrogen replacement could decrease the expression of P2X3 receptor in both mRNA and protein level.
These results indicate that estrogen might modulate the transduction of facial pain by inhibiting P2X3 receptor in TG.
P2X3受体在三叉神经节（TG）中表达，并参与面部疼痛的传导。然而，不同雌激素水平下P2X受体介导伤害感受的机制尚未得到研究。
在本研究中，雌性大鼠被随机分为假手术组（sham）、卵巢切除组（OVX）和雌激素治疗组。每组均测试面部机械性疼痛阈值，并采集三叉神经节进行P2X3受体mRNA的实时PCR分析和蛋白水平的蛋白质印迹分析。
我们发现，OVX大鼠的机械性疼痛阈值与假手术大鼠相比显著降低。雌激素替代可逆转这种降低。OVX大鼠三叉神经节中P2X3 mRNA水平的表达显著增加，与蛋白水平上P2X3受体的增强一致。雌激素替代可降低P2X3受体在mRNA和蛋白水平上的表达。
这些结果表明，雌激素可能通过抑制三叉神经节中的P2X3受体来调节面部疼痛的传导。
