Excitation–contraction coupling properties in women with work-related myalgia: a preliminary study

• Published in: Canadian journal of physiology and pharmacology Vol. 92; no. 6; pp. 498 - 506
• Main Authors: Green, Howard J, Ranney, Don, Burnett, Margaret, Galvin, Patti, Kyle, Natasha, Lounsbury, David, Ouyang, Jing, Smith, Ian C, Stewart, Riley, Tick, Heather, Tupling, A Russell
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.06.2014; Canadian Science Publishing NRC Research Press
• Subjects: Adenosine triphosphatase; Adult; Calcium; Calcium - metabolism; calcium regulation; Case-Control Studies; Comparative analysis; couplage excitation–contraction; Demographic aspects; Excitation Contraction Coupling; extensor carpi radialis brevis; Female; Fibromyalgia - metabolism; Health aspects; Humans; Middle Aged; muscle court extenseur radial du carpe; Muscle, Skeletal - metabolism; Muscular system; Myalgia; Myalgia - metabolism; myalgie; Occupational diseases; Occupational Diseases - metabolism; régulation du calcium; réticulum sarcoplasmique; sarcoplasmic reticulum; Sarcoplasmic Reticulum - metabolism; Sarcoplasmic Reticulum Calcium-Transporting ATPases - metabolism; Sodium-Potassium-Exchanging ATPase - metabolism; Tissues; trapezius; trapèze; travail; Women; work; Working women; Young Adult; Canada; couplage excitation–contraction; calcium regulation; myalgia; work; myalgie; excitation–contraction coupling; sarcoplasmic reticulum; trapezius; trapèze; régulation du calcium; muscle court extenseur radial du carpe; travail; réticulum sarcoplasmique; extensor carpi radialis brevis
• ISSN: 0008-4212; 1205-7541
• DOI: 10.1139/cjpp-2014-0029

We investigated the potential role of selected excitation–contraction coupling processes in females with work-related myalgia (WRM) by comparing WRM with healthy controls (CON) using tissue from extensor carpi radialis brevis (ECRB) and trapezius (TRAP) muscles. For the ECRB, age (mean ± SE) was 29.6 ± 3.5 years for CON (n = 9) and 39.2 ± 2.8 years for WRM (n = 13), while for the TRAP, the values were 26.0 ± 2.1 years for CON (n = 7) and 44.6 ± 2.9 years for WRM (n = 11). For the sarcoplasmic reticulum (SR) of the ECRB, WRM displayed concentrations (nmol·(mg protein) −1 ·min −1 ) that were lower (P < 0.05) for Total (202 ± 4.4 vs 178 ± 7.1), Basal (34 ± 1.6 vs 30.1 ± 1.3), and maximal Ca 2+ -ATPase activity (V max , 168 ± 4.9 vs 149 ± 6.3), and Ca 2+ -uptake (5.06 ± 0.31 vs 4.13 ± 0.29), but not SERCA1a and SERCA2a isoforms, by comparison with CON. When age was incorporated as a co-variant, Total, Basal, and Ca 2+ -uptake remained different from CON (P < 0.05), but not V max (P = 0.13). For TRAP, none of the ATPase properties differed between groups (P > 0.05) either before or following adjustment for age. No differences (P > 0.05) were observed between the groups for Ca 2+ -release in the SR for either TRAP or ECRB. Similarly, no deficiencies, regardless of muscle, were noted for either the Na + –K + -ATPase content or the α and β subunit isoform distribution in WRM. This preliminary study provides a basis for further research, with expanded numbers, investigating the hypothesis that abnormalities in SR Ca 2+ -regulation are involved in the cellular etiology of WRM.