Fujita K, Nakanishi K, Sobue K, Ueki T, Asai K, Kato T
Department of Bioregulation Research, Nagoya City University Medical School, Nagoya, Japan.
Neurochem Int. 1998 Jul;33(1):41-9. doi: 10.1016/s0197-0186(05)80007-5.
We have investigated the effects of gap junction inhibitors, octanol, halothane, sodium propionate and lindane, on neuronal periodic Ca2+ transients in neuron-astrocyte coculture systems. Octanol reduced the amplitude and frequency of Ca2+ oscillations in dose-dependent manner. One mM octanol caused a complete disappearance of Ca2+ oscillations. Similar suppressions were obtained by halothane (1 mM) and sodium propionate (25 mM). In contrast, lindane (300 nM) uniquely raised the basal level of [Ca2+], in oscillating neurons as well as the height of apparent amplitude without changes in the frequency. The current results imply that octanol, halothane and sodium propionate might lower the frequency of spontaneous Ca2+ oscillations by blocking the gap junctional communication of neighboring astrocytes and that lindane, though also blocking the gap junctions, might not affect the frequency but reversely increase both the basal [Ca2+]i and the amplitude, probably due to an increase of neuronal [Ins (1.4.5)P3]i. These findings strongly suggest that astrocytes contribute to the generation of periodic neuronal Ca2+ oscillations through astrocytic gap junctional communications and/or other signaling components between astrocytes and neurons.
我们研究了缝隙连接抑制剂辛醇、氟烷、丙酸钠和林丹对神经元 - 星形胶质细胞共培养系统中神经元周期性Ca2+瞬变的影响。辛醇以剂量依赖性方式降低Ca2+振荡的幅度和频率。1 mM辛醇导致Ca2+振荡完全消失。氟烷（1 mM）和丙酸钠（25 mM）也得到了类似的抑制效果。相比之下，林丹（300 nM）独特地提高了振荡神经元中[Ca2+]的基础水平以及表观幅度的高度，而频率没有变化。目前的结果表明，辛醇、氟烷和丙酸钠可能通过阻断相邻星形胶质细胞的缝隙连接通讯来降低自发Ca2+振荡的频率，而林丹虽然也阻断缝隙连接，但可能不影响频率，反而增加基础[Ca2+]i和幅度，这可能是由于神经元[Ins(1,4,5)P3]i增加所致。这些发现强烈表明，星形胶质细胞通过星形胶质细胞缝隙连接通讯和/或星形胶质细胞与神经元之间的其他信号成分，对周期性神经元Ca2+振荡的产生有贡献。
