In vitro increase in intracellular calcium concentrations induced by low or high extracellular glucose levels in ependymocytes and serotonergic neurons of the rat lower brainstem
In vitro increase in intracellular calcium concentrations induced by low or high extracellular glucose levels in ependymocytes and serotonergic neurons of the rat lower brainstem
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DOI：
10.1210/en.2003-1191
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发表时间：
2004-05-01
期刊：
影响因子：
4.8
通讯作者：
Maeda, KI
中科院分区：
文献类型：
--
作者：
Moriyama, R;Tsukamura, H;Maeda, KI
胰葡萄糖激酶（GK）样免疫反应位于大鼠脑的室管膜细胞和肾上腺素能神经元。本研究在体外研究了雄性大鼠中央管壁（CC）、中缝隐核（ROb）、下丘脑腹内侧（VMH）和下丘脑外侧区（LHA）的分离细胞中，细胞内钙浓度（[Ca 2 +]（i））响应于低（2 mM）或高（20 mM）细胞外葡萄糖浓度的变化。当细胞外葡萄糖水平从10 mM分别改变为2 mM或20 mM时，在CC（21.1%或9.8%的室管膜细胞）、ROb（10.9%或14.5%的肾上腺素能神经元）、VMH（7.8%和25.2%的神经元）和LHA（20%或15.7%的神经元）的细胞中发现[Ca 2 +]（i）增加。在CC（96.8%）和ROb（100%），对葡萄糖变化有反应的室管膜细胞和肾上腺素能神经元大多数对抗GK抗体呈免疫反应。[Ca ~（2+）]（i）的增加被无钙培养基或L-型钙通道阻滞剂阻断。响应于低葡萄糖而增加[Ca 2 +]（i）的细胞对高葡萄糖没有响应，反之亦然。急性四氧嘧啶治疗抑制GK活性阻断了低或高葡萄糖诱导的[Ca 2 +]（i）CC或ROb中大多数GK免疫反应性细胞的增加。VMH和LHA神经元中葡萄糖敏感性[Ca 2 +]（i）增加也是四氧嘧啶敏感性的，但从VMH和LHA中取出的细胞对所使用的抗体没有免疫反应性。本研究进一步表明，CC室管膜细胞和ROb中的β-肾上腺素能神经元也以GK依赖的方式对细胞外葡萄糖的变化敏感，但这些细胞中的GK亚型可能不同于VMH和LHA中的GK亚型。
Pancreatic glucokinase (GK)-like immunoreactivities are located in ependymocytes and serotonergic neurons of the rat brain. The present study investigated in vitro changes in intracellular calcium concentrations ([Ca2+](i)) inresponse to low (2 mM) or high (20 mM) extracellular glucose concentrations in isolated cells from the wall of the central canal ( CC), raphe obscurus nucleus (ROb), ventromedial hypothalamus (VMH), and lateral hypothalamic area (LHA) in male rats. An increase in [Ca2+](i) was found in cells from the CC (21.1% or 9.8% of ependymocytes), ROb (10.9% or 14.5% of serotonergic neurons), VMH(7.8% and 25.2% of neurons), and LHA(20% or 15.7% of neurons), when extracellular glucose levels were changed from 10 to either 2 or 20 mM, respectively. Most of the ependymocytes and serotonergic neurons responding to the glucose changes were immunoreactive to the anti-GK in the CC (96.8% for low glucose and 100% for high glucose) and ROb (100% for low and high glucose). The [Ca2+](i) increase was blocked with calcium-free medium or L-type calcium channel blocker. Cells with an increase in [Ca2+](i) in response to low glucose did not respond to high glucose and vice versa. Inhibition of GK activity with acute alloxan treatment blocked low or high glucose-induced [Ca2+](i) increases in most GK-immunoreactive cells from the CC or ROb. The glucose- sensitive [Ca2+](i) increase in neurons of the VMH and LHA was also alloxan-sensitive, but no cells taken from the VMH and LHA were immunoreactive to the antibody used. The present study further indicates that ependymocytes of the CC and serotonergic neurons in the ROb are also sensitive to the changes in extracellular glucose in a GK-dependent manner, but that the subtype of GK in these cells could be different from that in the VMH and LHA.