在外源性和内源性高乳酸血症期间,人类大脑中偏好的乳酸代谢
Jodie L Koep1,2, Jennifer S Duffy3, Jay M J R Carr4
1School of Health & Exercise Sciences, University of British Columbia - Okanagan, Kelowna, BC, Canada.
The Journal of physiology
|October 2, 2025
概括
人类大脑在循环中乳酸水平上升时优先使用乳酸作为燃料,无论是输液还是运动. 这种乳酸氧化减少了葡萄糖的利用,为其他大脑功能节省了葡萄糖.
科学领域:
- 神经科学是一个神经科学.
- 代谢过程中的代谢.
- 人体生理学 人体生理学
背景情况:
- 大脑主要使用葡萄糖作为能量,但由于葡萄糖代谢随着年龄的增长和某些病理而下降,人们正在寻找替代燃料.
- 研究乳酸作为一种替代的大脑燃料来源对于理解大脑能量代谢和潜在的治疗策略至关重要.
- 大脑对乳酸盐升高的代谢反应,比较外源输液与内源生产,仍然不完全理解.
研究的目的:
- 为了确定循环中乳酸的升高是否会在健康的人类大脑中产生节糖效应.
- 为了比较大脑对外源性 (乳酸盐输注) 和内源性 (运动诱导) 超乳酸血的代谢反应.
- 在不同的超乳酸血症条件下,量化乳酸对大脑总氧化代谢的贡献.
主要方法:
- 健康的成年人接受了静脉注射的乳酸和自行车运动,以达到匹配的动脉乳酸度 (∼4和∼8 mmol/l).
- 使用Duplex超声波测量大脑血流 (CBF).
- 分析了动脉和内静脉血液样本,以计算葡萄糖 (CMRGlc),乳酸 (CMRiLac) 和氧气 (CMRO2) 的大脑代谢率.
主要成果:
- 大脑氧气代谢率 (CMRO2) 保持不变,而大脑葡萄糖代谢率 (CMRGlc) 随着乳酸的增加而因剂量而有所下降.
- 在输液和运动条件下,大脑乳酸代谢 (CMRiLac) 显著增加并取决于剂量.
- 在乳酸8mmol/l时,循环中的乳酸对大脑总氧化代谢的贡献约为24%,无论乳酸来源如何.
结论:
- 升高的循环乳酸促进了人类大脑中偏好的乳酸氧化,减少了葡萄糖的利用.
- 这种节能葡萄糖的效果是一致的,无论乳酸是通过外源供应还是通过运动内源产生的.
- 乳酸作为大脑的重要替代氧化基质,特别是在超乳酸血的条件下.
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