UPTAKE AND RELEASE OF GLYCINE IN CEREBELLAR GRANULE CELLS AND ASTROCYTES IN PRIMARY CULTURE - POTASSIUM-STIMULATED RELEASE FROM GRANULE CELLS IS CALCIUM-DEPENDENT
UPTAKE AND RELEASE OF GLYCINE IN CEREBELLAR GRANULE CELLS AND ASTROCYTES IN PRIMARY CULTURE - POTASSIUM-STIMULATED RELEASE FROM GRANULE CELLS IS CALCIUM-DEPENDENT
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DOI：
10.1002/jnr.490240306
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发表时间：
1989-11-01
影响因子：
4.2
通讯作者：
KONTRO, P
中科院分区：
文献类型：
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作者：
HOLOPAINEN, I;KONTRO, P
[3 H]甘氨酸的摄取和释放的特性进行了研究与小脑颗粒细胞，在体外7-9天，（DIV）和星形胶质细胞，14-15 DIV，在原代培养。甘氨酸在两种细胞中的摄取均由可饱和的高亲和力转运和非饱和的扩散组成。颗粒细胞的转运常数（Km）和最大速度（V）明显高于星形胶质细胞。摄取是严格的Na+依赖性，也显着减少在低氯介质。在两种细胞类型中摄取的特异性相似。颗粒细胞和星形胶质细胞自发释放甘氨酸速度快。Homoexchange与细胞外添加的甘氨酸在颗粒细胞表明，流出至少部分介导的膜转运网站在这些细胞。红藻氨酸在神经元中比在神经胶质细胞中更有效地刺激释放，该效果显然是由两种细胞类型中的特定红藻氨酸敏感受体介导的。的释放被增强的藜芦碱和高K（50 mM）在神经元和星形胶质细胞的细胞膜的去极化。钾刺激的释放在神经元中是部分钙依赖的，但在胶质细胞中是钙非依赖的。结果表明，甘氨酸在小脑星形胶质细胞和小脑颗粒细胞中的功能作用。
The properties of [3H]glycine uptake and release were studied with cerebellar granule cells, 7-9 days in vitro, (DIV) and astrocytes, 14-15 DIV, in primary cultures. The uptake of glycine in both cell types consisted of a saturable high-affinity transport and non-saturable diffusion. The transport constant (Km) and maximal velocity (V) were significantly higher in granule cells than in astrocytes. Uptake was strictly Na+-dependent and also markedly diminished in low-Cl medium. The specificity of the uptake was similar in both cell types. The spontaneous release of glycine from granule cells and astrocytes was fast. Homoexchange with extracellularly added glycine in granule cells suggests that the efflux is at least partly mediated via membrane transport sites in these cells. Kainate stimulated the release more effectively in neurons than in glial cells, the effect apparently being mediated by specific kainate-sensitive receptors in both cell types. The release was enhanced by veratridine and by depolarization of cell membranes by high K (50 mM) in both neurons and astrocytes. The potasium-stimulated release was partially Ca-dependent in neurons but Ca-independent in glial cells. The results suggest a functional role for glycine in both cerebellar astrocytes and glutamatergic granule cells.