Effect of endurance exercise on the Ca2+ pumps from transverse tubule and sarcoplasmic reticulum of rabbit skeletal muscle

• Published in: Journal of applied physiology (1985) 2004-08, Vol.97 (2), p.467-474
• Main Authors: Becker, Viola, Gonzalez-Serratos, Hugo, Alvarez, Rocio, Baermann, Michael, Irles, Claudine, Ortega, Alicia
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological - physiology; Adenosine Triphosphate - metabolism; Animals; Biological and medical sciences; Calcium; Calcium - metabolism; Calcium-Transporting ATPases - metabolism; Calorimetry, Differential Scanning; Exercise; Fundamental and applied biological sciences. Psychology; Male; Microsomes - metabolism; Muscle Fatigue - physiology; Muscle Fibers, Fast-Twitch - physiology; Muscle, Skeletal - cytology; Muscle, Skeletal - physiology; Muscular system; Physical Endurance - physiology; Rabbits; Sarcoplasmic Reticulum - enzymology; Sarcoplasmic Reticulum Calcium-Transporting ATPases
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00906.2003

1 Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de Mexico, México City 04510, México; 2 Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201; 3 Department of Physics E22 (Biophysics), Technical University of Munich, 80333 Garching, Germany; and 4 Departamento de Bioquímica, Instituto Nacional de Perinatología, México City 11000, México Submitted 25 August 2003 ; accepted in final form 10 March 2004 The sarcoplasmic reticulum (SR) Ca 2+ pump is the main homeostatic regulatory mechanism in fast skeletal muscle that maintains intracellular Ca 2+ concentration ([Ca 2+ ] i ) at the nanomolar level at rest. The transverse tubule (TT) Ca 2+ pump transports cytosolic Ca 2+ to the extracellular space. During prolonged muscular activity, [Ca 2+ ] i may increase. TT and SR isolated microsomal vesicles were highly purified, and the purity was checked by immunoblotting. The present study shows the effects of endurance exercise on the activities and structures of the TT and SR Ca 2+ pumps of fast skeletal muscle from rabbit at rest. The Ca 2+ pump activity increased manifolds in TT but did not change in SR. The protein denaturalization profiles obtained by differential scanning calorimetry showed 1 ) a shift in the transition temperature and an increase in the enthalpy of the TT Ca 2+ pump and 2 ) a significant change in the transition temperature of the SR Ca 2+ pump Ca 2+ -binding domain. We conclude that the TT Ca 2+ pump activity was upgraded in association with structural changes to handle the changes in [Ca 2+ ] i and TT lumen Ca 2+ concentration that occur during endurance exercise. muscle adaptation; exercise training Address for reprint requests and other correspondence: A. Ortega, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, México City AP 70-159, CP 04510 (E-mail: aortega{at}servidor.unam.mx ).