Effects and mechanism of quercetin on electric current of Nav1.8 in rat dorsal root ganglion neurons

To study the effects of quercetin(Que)on the electric current of Nav1. 8(I_{Nav1. 8})in rat dorsal root ganglion(DRG)neurons, dose-effect relationship of Que on I_{Nav1. 8} and the activation and inactivation properties of voltage-dependent Nav1. 8 influenced by Que were studied by using the whole-cell patch clamp technique in fresh isolated rat DRG neurons. It was found that diffeent concerntrations of Que(10, 30, 100 μmol/L)could inhibit I_{Nav1. 8} peak value of DRG neurons in concentration-dependent manner. The inhibition of peak currents were(15. 32±3. 43)%, (22. 92±8. 24)% and(47. 29±11. 42)% respectively, the IC₅₀ was 121. 38 μmol/L and the Hill coefficient was 0. 76. In the existence of Que(100 μmol/L), the activation curve of Nav1. 8 channel in DRG was slightly shifted to depolarizing direction for 0. 83 mV, and the inactivation curve was shifted to hyperpolarizing direction for 1. 86 mV. Compared with the stage before intervention, the half-activation voltage(V_1/2=-40. 23±0. 25 mV)was significantly different(P< 0. 01). In conclusion, Que inhibits the Nav1. 8 channel activity in dose and voltage-dependent manner, which may count for the reduction of algesthesia transmission and the alleviation of chronic visceral pain.