Leegsma-Vogt Gea, Venema Kor, Korf Jakob
Department of Psychiatry, Section of Biological Psychiatry, University of Groningen, Groningen, The Netherlands.
J Cereb Blood Flow Metab. 2003 Aug;23(8):933-41. doi: 10.1097/01.WCB.0000080650.64357.8F.
Lactate derived from glucose can serve as an energy source in the brain. However, it is not certain how much lactate, directly taken from the blood circulation, may replace glucose as an energy source. This study aimed to estimate the uptake, release, and utilization of lactate entering the brain from the blood circulation. The change in cerebral venous-arterial glucose and lactate differences after lactate infusions in the anesthetized rat were measured. Ultrafiltration probes were placed in the aorta and in the jugular vein, and connected to a flow injection analysis system with biosensors for glucose and lactate. Measurements were taken every minute. Lactate efflux was observed at baseline, whereas an influx of lactate was seen during lactate infusion. Immediately after the infusion there was a net efflux of lactate from the brain. The results suggest that the majority of lactate moving into the brain is not used as an energy substrate, and that lactate does not replace glucose as an energy source. Instead, the authors propose the concept of a lactate pool in the brain that can be filled and emptied in accordance with the blood lactate concentration, but which is not used as an energy supply for cerebral metabolism.
源自葡萄糖的乳酸盐可作为大脑的能量来源。然而，直接从血液循环中获取的乳酸盐能在多大程度上替代葡萄糖作为能量来源尚不确定。本研究旨在评估从血液循环进入大脑的乳酸盐的摄取、释放及利用情况。测量了麻醉大鼠输注乳酸盐后脑静脉 - 动脉葡萄糖和乳酸盐差值的变化。将超滤探头置于主动脉和颈静脉中，并连接到带有葡萄糖和乳酸盐生物传感器的流动注射分析系统。每分钟进行测量。在基线时观察到乳酸盐外流，而在输注乳酸盐期间则出现乳酸盐内流。输注后立即出现乳酸盐从大脑的净外流。结果表明，进入大脑的大部分乳酸盐并非用作能量底物，且乳酸盐不能替代葡萄糖作为能量来源。相反，作者提出大脑中存在乳酸盐池的概念，该乳酸盐池可根据血液乳酸盐浓度进行填充和排空，但并非用作大脑代谢的能量供应。
