{Reference Type}: Case Reports
{Title}: Are abnormalities in sarcoplasmic reticulum calcium cycling properties involved in trapezius myalgia?: case studies on three females.
{Author}: Green HJ;Galvin P;Ranney DA;Tick H;Ouyang J;
{Journal}: Am J Phys Med Rehabil
{Volume}: 90
{Issue}: 10
{Year}: Oct 2011
{Factor}: 3.412
{DOI}: 10.1097/PHM.0b013e31821f6f1f
{Abstract}: <B>OBJECTIVE: </B>The aim of this study was to demonstrate the feasibility of using samples obtained through muscle biopsy to assess a wide range of cellular properties, some of which may be abnormal in myalgia. Given the recent emphasis on the role of excitation-contraction coupling in health and disease, special emphasis is given to the characterization of the properties involved in this process.<BR><B>METHODS: </B>Tissue samples were obtained from the upper portion of the descending trapezius muscle in three female patients (PAT) with clinically diagnosed myalgia and assessed for a spectrum of properties related to substrate use, energy production, and excitation-contraction coupling and were compared with samples from three healthy controls.<BR><B>RESULTS: </B>At the level of organization of the metabolic pathways, all PAT generally displayed normal activities of enzymes representing the potential for oxidative phosphorylation, glucose phosphorylation, glycolysis, and lactate oxidation. In contrast, a reduced potential was observed in PAT for both fat oxidation (-20%) and high-energy phosphate transfer (-38%). For excitation-contraction coupling, PAT had a compromised sarcoplasmic reticulum maximal Ca-ATPase activity (-21%), Ca uptake (-44%), and sarcoplasmic endopleasmic reticulum (SERCA) expression for both SERCA1a (-16%) and SERCA2a (-17%), which were accompanied by a lower phase 2 Ca release (-45%). The Na-K-ATPase concentration, the enzyme-regulating membrane excitability via active Na and K seemed elevated (+25%) in PAT.<BR><B>CONCLUSIONS: </B>These results demonstrate the feasibility of analyzing tissue samples for a wide range of properties and provide a rationale for studies examining the cellular basis of myalgia with particular emphasis on sarcoplasmic reticulum Ca cycling, given the latter's role in regulating a wide range of cellular functions.