龙血素B诱导大鼠初级感觉神经元胞内Ca^(2+)浓度缓慢上调(英文)

Slow rise of intracellular Ca^(2+) concentration in rat primary sensory neurons triggered by loureirin B

本研究采用Fura-2荧光染色的方法,在急性分离的背根神经节(dorsal root ganglia,DRG)神经元细胞上,观察了由传统中药龙血竭活性成分龙血素B诱导的[Ca2+]i的变化。在DRG细胞上施加龙血素B引起[Ca2+]i的上升,且存在剂量依赖效应。同样的结果出现在细胞外液无钙的情况,但此时[Ca2+]i上升幅度远远小于在标准细胞外液情况下出现的上升幅度。这表明DRG的[Ca2+]i的升高主要是由细胞外Ca2+内流而产生的,而不是由细胞器如线粒体和胞内钙库释放Ca2+产生的。另外,咖啡因和龙血素B共孵育也可以诱导[Ca2+]i的升高,但是其上升幅度显著小于单独施加咖啡因时的幅度,说明龙血素B与咖啡因作用的通路或靶器有所重叠。与咖啡因、高钾和辣椒素诱导的瞬变相比,龙血素诱导的DRG的[Ca2+]i的上升更加缓慢且持续时间较长。这些结果提示,龙血素B诱发的初级感觉神经元[Ca2+]i的升高是稳定且独特的。

In the present study, the intracellular free calcium concentration （[Ca^2＋]i） in acutely isolated rat dorsal root ganglia （DRG） neurons modulated by loureirin B, an active component of ＂dragon＇ s blood＂ which is a kind of Chinese herbal medicine, was determined by the means of Fura-2 based microfluorimetry. It was found that lonreirin B could evoke the elevation of [Ca^2＋]i in a dose-dependent manner. However, the elevation of [Ca^2＋]i evoked in the calcium free solution was much smaller than that in the standard external cell solution, suggesting that most change of [Ca^2＋]i was generated by the influx of extracellular Ca^2＋, not by the activities of intracellular organelles like Ca^2＋ stores and mitochondria. In addition, the mixture of loureirin B and caffeine also induced [Ca^2＋]i rise, but the peak of [Ca^2＋]i rise induced by the mixture was significantly lower than that by caffeine alone, which means the triggering pathway and the targets of caffeine are probably involved in loureirin B-induced [Ca^2＋]i rise. Moreover, compared to the transients induced by caffeine, KCl and capsaicin, the loureirin B-induced [Ca^2＋]i rise is much slower and more stable. These results indicate that the capability of loureirin B of inducing the [Ca^2＋]L rise is solid and unique.