Effects of magnesium sulfate on dynamic changes of brain glucose and its metabolites during a short-term forced swimming in gerbils.
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.
Cheng
Shiu-Min
SM
Institute of Physiology, National Yang-Ming University, Taipei, 112, Taiwan.
Yang
Dar-Yu
DY
Lee
Chien-Pin
CP
Pan
Hung-Chuan
HC
Lin
Mao-Tsun
MT
Chen
Ssu-Hua
SH
Cheng
Fu-Chou
FC
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D004734:Energy Metabolism / Q000502:physiology; D005110:Extracellular Space / Q000378:metabolism; D005849:Gerbillinae; D005947:Glucose / Q000378:metabolism*; D008278:Magnesium Sulfate / Q000494:pharmacology*; D008297:Male; D017551:Microdialysis; D017072:Neostriatum / Q000378:metabolism; D019289:Pyruvic Acid / Q000097:blood; D013550:Swimming / Q000502:physiology*
D008278:Magnesium Sulfate; D019289:Pyruvic Acid; D005947:Glucose