Zimprich F, Gailey M, Bolsover S R
Department of Physiology, University College London, UK.
Brain Res Dev Brain Res. 1994 Jul 15;80(1-2):7-12. doi: 10.1016/0165-3806(94)90083-3.
We have examined the effect of cytosolic calcium concentration ([Ca2+]i) on neurite outgrowth in two neuronal cells, cerebellar granule cells and N1E-115 neuroblastoma cells. The set point [Ca2+]i in unstimulated cells bathed in normal extracellular medium was 37 nM and 108 nM, respectively. When we altered extracellular calcium concentration to cause small excursions of [Ca2+]i either above or below the set point, neurite outgrowth from granule cells declined. Thus granule cells show the bell-shaped dependence of neurite outgrowth on [Ca2+]i characteristic of sensory and other neurones [Dev. Brain Res., 70 (1992) 287-290; The Axon, Oxford University Press, New York, 1994]. In contrast, neurite outgrowth from N1E-115 cells increased monotonically as [Ca2+]i was reduced. This result, which is consistent with results obtained by studying individual growth cones [J. Neurosci., 9 (1989) 4007-4020], implies that these transformed cells are aberrant in having no bell-shaped dependence of neurite outgrowth on [Ca2+]i. In both cell types an increase of [Ca2+]i above the set point reduced neurite outgrowth. However, this decline did not persist as [Ca2+]i was set to increasingly high levels by increasing extracellular calcium. Rather, in both cell types, an increase of extracellular calcium above 6.9 mM produced a second, increasing phase of neurite outgrowth.
我们研究了胞质钙浓度（[Ca2+]i）对两种神经元细胞（小脑颗粒细胞和N1E-115神经母细胞瘤细胞）神经突生长的影响。在正常细胞外培养基中培养的未受刺激细胞的设定点[Ca2+]i分别为37 nM和108 nM。当我们改变细胞外钙浓度以使[Ca2+]i在设定点之上或之下有小幅度波动时，颗粒细胞的神经突生长减少。因此，颗粒细胞表现出神经突生长对[Ca2+]i呈钟形依赖，这是感觉神经元和其他神经元的特征[《发育脑研究》，70 (1992) 287 - 290；《轴突》，牛津大学出版社，纽约，1994]。相比之下，随着[Ca2+]i降低，N1E-115细胞的神经突生长单调增加。这一结果与通过研究单个生长锥获得的结果一致[《神经科学杂志》，9 (1989) 4007 - 4020]，表明这些转化细胞异常，其神经突生长对[Ca2+]i没有钟形依赖。在两种细胞类型中，[Ca2+]i高于设定点都会减少神经突生长。然而，随着细胞外钙浓度增加使[Ca2+]i设定到越来越高的水平时，这种减少并没有持续。相反，在两种细胞类型中，细胞外钙浓度增加到6.9 mM以上会产生神经突生长的第二个增加阶段。
