The Hong Kong Journal of Sports Medicine and Sports

Volume XI, Nov, 2000

The Effects of the Overdrive and The Protective Function of Mg+2 Un Isolated Rat Heart

Chengdu College of Physical Education

Shandon Yiantai Teachers' College

Sichuan West-China Medical University

The objectives of the present study were to research further the variation of heart function in fatigue condition and to explore new method to eliminate and recover horn fatigue and protect fatigued heart function. 36 m SD female rats were randomly divided into 3 groups: Group A - not stimulated; group B - perfused and recovered with normal magnesium solution and group C - perfused and recovered with high magnesium (2.4 mmol/L). Connected the isolated heart with Langendorff heart preparations and perfused with normal magnesium solution, group A received no stimulation, overdrive of 10 volt. For groups B and C, 600 times/min were administered for 30 minutes and then perfused with normal magnesium and high magnesium solution for 20 minutes respectively. Parameters of hydrodynamic, activity of myocardium enzyme (LDH), level of lipid oxidation and variation of calcium were measured.

The results showed that after the stimulation the hearts gave signs of hypoxia and ischemia. In normal magnesium group, LVSP ± dp/dt max decreased, LDH and MDA contents were elevated, activity of GSH-px decreased, calcium in myocardium and mitochondrion increased (p<0.05). In high magnesium, the parameters showed no significant difference compared with group A (p>0.05), which indicated that high magnesium solution perfusion had a good effect in the recovering of the fatigued hearts.

Key Words : Fatigue recovering, Langendorff perfusion, overdrive, myocardium enzymes.

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