Li X, Yokono K, Okada Y
Department of Physiology, Kobe University School of Medicine, 7-5-1, Kusunoki-co, Chuo-ku, 650-0017, Kobe, Japan.
Neurosci Lett. 2000 Nov 17;294(2):81-4. doi: 10.1016/s0304-3940(00)01535-4.
To clarify the importance of glucose metabolism in maintaining neural activity, we investigated the effects of lowering the concentration of glucose in perfusion medium on synaptic activity (population spikes, PS) and on the level of high energy phosphates in the region of dentate gyrus (DG), CA3 and CA1 area of hippocampal slices of guinea pig. Further we determined the activity of phosphofructokinase (PFK) and hexokinase (HK) of these areas. Lowering the concentration of glucose from 10 to 5, 4, 3, 1 and 0 (mM) caused a reduction in the PS amplitude. The PS in CA3 and CA1 region decayed and extinguished much faster than that in DG area. The ATP and CrP levels in these three areas were well preserved even after lowering the concentration of glucose to 3mM, and the patterns of reduction showed no difference in these three areas. On the other hand, there were significant differences in the activity of PFK in the DG, CA3 and CA1 areas, in contrast with HK which showed no significant differences. PFK activity was highest in the DG area and followed by CA3 and CA1 regions. The sensitivity in maintaining synaptic activity to lowered glucose concentrations showed good parallels with the activity of PFK in these regions, indicating that non-oxidative glycolytic metabolism regulated by PFK is crucial for the maintenance of synaptic activity
为阐明葡萄糖代谢在维持神经活动中的重要性，我们研究了降低灌注培养基中葡萄糖浓度对豚鼠海马切片齿状回（DG）、CA3和CA1区的突触活动（群体峰电位，PS）以及高能磷酸盐水平的影响。此外，我们还测定了这些区域的磷酸果糖激酶（PFK）和己糖激酶（HK）的活性。将葡萄糖浓度从10 mM降至5、4、3、1和0 mM会导致PS振幅降低。CA3和CA1区的PS衰减和消失比DG区快得多。即使将葡萄糖浓度降至3 mM，这三个区域的ATP和磷酸肌酸（CrP）水平仍能很好地保持，且降低模式在这三个区域没有差异。另一方面，DG、CA3和CA1区的PFK活性存在显著差异，而HK活性则无显著差异。PFK活性在DG区最高，其次是CA3和CA1区。维持突触活动对降低葡萄糖浓度的敏感性与这些区域的PFK活性表现出良好的相关性，表明由PFK调节的非氧化糖酵解代谢对于维持突触活动至关重要。
