Study of Biophysical Properties of L-type Calcium Channel in Rat Myocardial Cells with Exercise-induced Fatigue

Objective:To study the effects of exercise-induced fatigue on myocardial cells L-type calcium currents and biophysical properties in rats;to prove that L-type Ca2+ channel participates directly in the change of i.due to exercise-induced fatigue.Methods:48 rats,male or female,were divided into control group and exercise-induced fatigue group randomly.15 days endurance swimming training was adopted to establish exercise-induced fatigue models;patch clamp technique was applied to examine the effects of exercise-induced fatigue on myocardial L-type calcium currents in rats.Results:1)The whole cell L-type Ca2+ channel peak currents obviously increased in exercise-induced fatigue rats:the whole cell L-type Ca2+ channel peak currents increased from-470±11.73pA to-819.90±10.78pA(n=8,P<0.05),the exercise-induced fatigue group increased 74.60% compared with the control group.2) Using patch clamp technique to examine the activation of L-type Ca2+ channel currents and dynamic properties of inactivation channel:Inactivation curve shifted to the right in the exercise-induced fatigue group compared with the control group,activation curve in the exercise-induced fatigue group did not alter compared with the control group.Conclusion:Exercise-induced fatigue changes biophysical property of L-type Ca2+ channel,and enhances L-type Ca2+ channel currents and causes disorders in calcium balance adjustment.