INTRACELLULAR FREE CALCIUM RESPONSES TO PROTONS AND CAPSAICIN IN CULTURED TRIGEMINAL NEURONS
INTRACELLULAR FREE CALCIUM RESPONSES TO PROTONS AND CAPSAICIN IN CULTURED TRIGEMINAL NEURONS
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DOI：
10.1016/0306-4522(95)00055-n
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发表时间：
1995-07-01
期刊：
影响因子：
3.3
通讯作者：
VALDEOLMILLOS, M
中科院分区：
文献类型：
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作者：
GARCIAHIRSCHFELD, J;LOPEZBRIONES, LG;VALDEOLMILLOS, M
酸性溶液和辣椒素是伤害性神经元的选择性化学刺激。在培养的新生兔三叉神经元上，分析了这些刺激对细胞内钙浓度的影响。在86%的神经元中，pH值的快速降低（从7.4至5）引起细胞内钙浓度的瞬时升高，平均超过基础水平（162.5 +/- 3.5 nM; n = 174）的270%。在pH 5.5下发现最大响应。质子诱导的瞬变减少或废除20 mM氯化钙，零氯化钙和1 μ M钌红。响应于1 μ M辣椒素，40%的细胞，对质子敏感，也增加了他们的细胞内钙离子浓度的218%的控制。辣椒素诱导的细胞内钙离子浓度升高由一个初始峰，随后是第二个，较慢的细胞内钙离子浓度升高。1 μ M钌红完全阻断辣椒素反应，并消失在零钙，但在高细胞外钙增强。细胞内钙离子浓度反应辣椒素仍然观察到神经元的质子反应脱敏持续暴露于低pH值（pH 6.5）。这些结果表明，细胞内钙离子浓度的升高由pH（0）和辣椒素的适度降低引起，通过不同的机制发生。
Acidic solutions and capsaicin are selective chemical stimuli for nociceptive neurons. The effect of these stimuli on intracellular calcium concentration was analysed in cultured trigeminal neurons of newborn rabbits. Rapid reductions in pH (from 7.4 to 5) evoked a transient rise in intracellular calcium concentration of 270% on average over the basal level (162.5 +/- 3.5 nM; n = 174) in 86% of the neurons. Maximal responses were found at pH 5.5. Proton-induced transients were diminished or abolished by 20 mM CaCl2, by zero CaCl2 and by 1 mu M Ruthenium Red. In response to 1 mu M capsaicin, 40% of the cells that were sensitive to protons also increased their intracellular calcium concentration to 218% of control. Capsaicin-induced intracellular calcium concentration rises were composed of an initial peak followed by a second, slower intracellular calcium concentration elevation. The capsaicin response was completely blocked by 1 mu M Ruthenium Red, and disappeared in zero calcium, but was augmented in high extracellular calcium. Intracellular calcium concentration responses to capsaicin were still observed in neurons whose response to protons was desensitized by sustained exposure to low pH (pH 6.5). Cells surviving a 10-24 h capsaicin (10 mu M) treatment, still displayed responses to pH reductions.These results suggest that intracellular calcium concentration rises induced by moderate reductions in; pH(0) and capsaicin occur through different mechanisms.