摘要或動機

Astrocytes provide energy to neuron mainly with lactate, which is transported through monocarboxylate transporters (MCTs). Among 14 isoforms of MCTs reported in mammals, only MCT1, 2 and 4 are expressed in brain and the three isoforms are found to differentially expressed in neuron and astrocyte, respectively. Based on these, “astrocyte-neuron lactate shuttle” has been proposed. However, no in vivo evidence was available so far to support this hypothesis. In the present study, zebrafish was used as a model to provide in vivo molecular physiological evidence for the involvements of MCTs in the development and functioning of central nervous system (CNS). Full-length cDNAs of the zebrafish MCT1-4 were cloned from zebrafish. Based on RT-PCR results, zMCT1 and zGLUT4 expressed in brain were chosen for further experiment. Morpholino knockdown experiments provided for the 1st time the in vivo evidence to indicate that the zMCT1 and zMCT4 may be involved in energy translocation and functioning of the developing CNS. 於前人預備實驗中，發現斑馬魚胚胎時期肝醣訊號會於腦部與中樞神經系統區位出現。因此，醣類的分布與在細胞間的傳遞應可視為腦部發育的重要指標。我們以基因體資料庫為工具，研究斑馬魚腦部相關基因異構型分布。目前，我們選殖到數個葡萄糖運輸 (GLUT)、鈉離子/葡萄糖協同運輸(SGLT)與單羧基運輸(MCT)通道在斑馬魚腦部表現，其表現是否與胚胎初期中樞神經系統的發育相關仍未知。經過初步基因分析後，我們決定以MCT 中第一和四異構型作為研究對象，並用Anti-Hu，與PCNA 做神經觀測，將施打反股寡核?酸進行突變操作的斑馬魚，與對照組進行免疫染色分析，以螢光顯微鏡觀察發現：抑制MCT 表現，確實影響胚胎時期中樞神經細胞發育及鰓部細胞分裂；亦可能造成畸形出現。