Abstract
Long-term heavy load contractions decrease the relative amount of the myosin heavy chain (MHC) IIX isoform in human skeletal muscle, but the timing of the down-regulation in the short term is unknown. Untrained subjects performed two resistance bouts, in two consecutive days, with one leg, the other leg serving as a control (age 24±1, n=5). Muscle biopsies were obtained in both legs before, immediately after, and 24, 54, and 96 hours after exercise. Serial cryosection analysis combined immunohistochemistry and ATPase histochemistry with In Situ hybridization to identify the distribution of MHC isoforms and their corresponding transcripts, enabling identification of transitional fibers. Fibers positive solely for MHC IIX mRNA decreased in the exercised leg throughout the study period. At 96 hours post-exercise, no fibers solely expressed MHC IIX mRNA. In contrast, the number of fibers expressing MHC IIA mRNA increased throughout the study period. The percentage of fibers expressing mRNA for MHC I was unchanged in both legs at all time points. Pronounced depletion of glycogen in the MHC IIX fibers of the exercised leg verifies that the type IIX fibers were active during the heavy load contractions. Major mismatch between MHC at t...Continue Reading
References
Oct 1, 1970·Archives of Neurology·M H Brooke, K K Kaiser
Dec 1, 1994·The American Journal of Physiology·V SmerduS Schiaffino
Jun 1, 1994·Acta Physiologica Scandinavica·J L AndersenB Saltin
Jan 1, 1994·Acta Physiologica Scandinavica·J L AndersenB Saltin
Feb 1, 1997·Histochemistry and Cell Biology·Z QuS Zhou
Jun 1, 1997·The American Journal of Physiology·J L Andersen, S Schiaffino
Feb 4, 1999·Journal of Applied Physiology·J L AndersenS Schiaffino
Jul 7, 2000·Muscle & Nerve·J L Andersen, P Aagaard
Aug 2, 2000·Biophysical Journal·Z H HeC Reggiani
Aug 11, 2000·Italian Journal of Neurological Sciences·S SchiaffinoG Pallafacchina
Sep 8, 2000·Scientific American·J L AndersenB Saltin
Jul 18, 2002·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Jeffrey J WidrickDena P Garner
Aug 8, 2002·Medicine and Science in Sports and Exercise·Darryn S Willoughby, Matthew J Nelson
Nov 19, 2002·European Journal of Applied Physiology·Gerson E R CamposRobert S Staron
Aug 4, 2004·Pflügers Archiv : European journal of physiology·Peter KrustrupJens Bangsbo
Apr 15, 2006·Journal of Applied Physiology·David J KosekMarcas M Bamman
Apr 26, 2008·Journal of Applied Physiology·John K PetrellaMarcas M Bamman
Apr 1, 2010·Acta Physiologica·S Schiaffino
Sep 25, 2010·Scandinavian Journal of Medicine & Science in Sports·J L Andersen, P Aagaard
Oct 27, 2010·The Journal of Physiology·Meishan Li, Lars Larsson
Dec 7, 2010·Medicine and Science in Sports and Exercise·C Scott BickelMarcas M Bamman
Oct 21, 2011·Physiological Reviews·Stefano Schiaffino, Carlo Reggiani
Jan 30, 2015·Physiological Reports·Adam M GonzalezJeffrey R Stout
Mar 13, 2016·Annals of Anatomy = Anatomischer Anzeiger : Official Organ of the Anatomische Gesellschaft·Francesco MascarelloLisa Maccatrozzo
Citations
Mar 5, 2019·Acta Physiologica·Anders KarlsenAbigail L Mackey
Dec 10, 2019·The Journal of Physiology·Daniel HammarströmStian Ellefsen
Jun 23, 2019·BMC Public Health·Amy E PedenTessa Clemens
May 21, 2019·Acta Physiologica·Mathias Wernbom, Per Aagaard
Dec 2, 2020·BMC Bioinformatics·Yusuf KhanRafi Ahmad