Glycolysis Mediated Sarcoplasmic Reticulum Ca Signal Regulates Mitochondria Ca during Skeletal Muscle Contraction

Abstract

PURPOSE This study was to investigate the Glycolysis mediated sarcoplasmic reticulum (SR) Ca2+ signal regulates mitochondria Ca2+ during skeletal muscle contraction by using glycolysis inhibitor. METHODS To examine the effect of Glycolysis inhibitor on SR and mitochondria Ca2+ content, we used skeletal muscle fiber from gastrocnemius muscle. 2-deoxy glucose and 3-bromo pyruvate used as glycolysis inhibitor, it applied to electrically stimulated muscle contraction experiment. Intracellular Ca2+ content, SR, mitochondria Ca2+ level and mitochondria membrane potential (MMP) was detected by confocal microscope. Mitochondrial energy metabolism related enzyme, citric acid synthase activity also examined for mitochondrial function during the muscle contraction. RESULTS Treatment of 2-DG and 3BP decreased the muscle contraction induced SR Ca2+ increase however the mitochondria Ca2+ level was increased by treatment of inhibitors and showed and overloading as compared with the control group. Glycolysis inhibitor and thapsigargin treatment showed a significant decrease in MPP of skeletal muscle cells compared to the control group. CS activity significantly decreased after pretreatment of glycolysis inhibitor during skeletal muscle contraction. These results suggest that regulation of mitochondrial Ca2+ levels by glycolysis is an important factor in mitochondrial energy production during skeletal muscle contraction CONCLUSIONS These results suggest that mitochondria Ca2+ level can be regulated by SR Ca2+ level and glycolytic regulation of intraocular Ca2+ signal play pivotal role in regulation of mitochondria energy metabolism during the muscle contraction.

Keywords

• glycolysis
• endoplasmic reticulum
• mitochondria
• calcium.