Cheng Shiu-Min, Yang Dar-Yu, Lee Chien-Pin, Pan Hung-Chuan, Lin Mao-Tsun, Chen Ssu-Hua, Cheng Fu-Chou
Institute of Physiology, National Yang-Ming University, Taipei, 112, Taiwan.
Eur J Appl Physiol. 2007 Apr;99(6):695-9. doi: 10.1007/s00421-006-0374-7. Epub 2007 Feb 14.
This investigation examined the acute effects of magnesium on the dynamic changes of brain glucose, lactate, pyruvate and magnesium levels in conscious gerbils during forced swimming. Gerbils were pretreated with saline (control group) and magnesium sulfate (90 mg kg(-1), intraperitoneal injection) before a 15 min forced swimming period. The basal levels of glucose, pyruvate, lactate, and magnesium in brain dialysates were 338 +/- 18, 21 +/- 2, 450 +/- 39, and 2.1 +/- 0.1 microM, respectively, with no significant difference between groups. Magnesium levels were found slightly higher (but not significant) in the magnesium-treated group. However, brain glucose and pyruvate levels in the control group decreased to about 50 and 60% of the basal level (P = 0.01) after swimming, respectively. Pretreatment with magnesium sulfate immediately increased glucose levels to about 140% of the basal level, and increased pyruvate levels to about 150% of the basal level during forced swimming (P = 0.01). Both glucose and pyruvate levels returned to the basal level after 30 min of the recovery. The lactate levels of the control group increased to about 160% of the basal level (P = 0.01) during swimming, whereas pretreatment with magnesium sulfate attenuated lactate levels to 130% of the basal level (P = 0.01). Magnesium supplementation may be beneficial because it provides an additional glucose source and may also promote the recovery of energy substrates in the brain during and after forced exercise. In order to achieve optimal physical performance, further investigation as to dosage of magnesium supplementation is needed.
本研究考察了镁对清醒沙鼠在强迫游泳期间脑葡萄糖、乳酸、丙酮酸和镁水平动态变化的急性影响。在15分钟强迫游泳期之前，沙鼠分别用生理盐水（对照组）和硫酸镁（90mg/kg(-1)，腹腔注射）进行预处理。脑透析液中葡萄糖、丙酮酸、乳酸和镁的基础水平分别为338±18、21±2、450±39和2.1±0.1μM，两组间无显著差异。在镁处理组中发现镁水平略高（但不显著）。然而，游泳后对照组的脑葡萄糖和丙酮酸水平分别降至基础水平的约50%和60%（P=0.01）。在强迫游泳期间，用硫酸镁预处理可立即将葡萄糖水平提高至基础水平的约140%，并将丙酮酸水平提高至基础水平的约150%（P=0.01）。恢复30分钟后，葡萄糖和丙酮酸水平均恢复至基础水平。对照组的乳酸水平在游泳期间增加至基础水平的约160%（P=0.01），而用硫酸镁预处理可将乳酸水平减弱至基础水平的130%（P=0.01）。补充镁可能有益，因为它提供了额外的葡萄糖来源，并且还可能促进强迫运动期间及之后大脑中能量底物的恢复。为了达到最佳身体表现，需要进一步研究镁补充剂的剂量。
