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dc.contributor.authorBowslaugh, Joshua
dc.date.accessioned2016-04-21T12:42:48Z
dc.date.available2016-04-21T12:42:48Z
dc.identifier.urihttp://hdl.handle.net/10464/9239
dc.description.abstractRegulatory light chain (RLC) phosphorylation in fast twitch muscle is catalyzed by skeletal myosin light chain kinase (skMLCK), a reaction known to increase muscle force, work, and power. The purpose of this study was to explore the contribution of RLC phosphorylation on the power of mouse fast muscle during high frequency (100 Hz) concentric contractions. To determine peak power shortening ramps (1.05 to 0.90 Lo) were applied to Wildtype (WT) and skMLCK knockout (skMLCK-/-) EDL muscles at a range of shortening velocities between 0.05-0.65 of maximal shortening velocity (Vmax), before and after a conditioning stimulus (CS). As a result, mean power was increased to 1.28 ± 0.05 and 1.11 ± .05 of pre-CS values, when collapsed for shortening velocity in WT and skMLCK-/-, respectively (n = 10). In addition, fitting each data set to a second order polynomial revealed that WT mice had significantly higher peak power output (27.67 ± 1.12 W/ kg-1) than skMLCK-/- (25.97 ± 1.02 W/ kg-1), (p < .05). No significant differences in optimal velocity for peak power were found between conditions and genotypes (p > .05). Analysis with Urea Glycerol PAGE determined that RLC phosphate content had been elevated in WT muscles from 8 to 63 % while minimal changes were observed in skMLCK-/- muscles: 3 and 8 %, respectively. Therefore, the lack of stimulation induced increase in RLC phosphate content resulted in a ~40 % smaller enhancement of mean power in skMLCK-/-. The increase in power output in WT mice suggests that RLC phosphorylation is a major potentiating component required for achieving peak muscle performance during brief high frequency concentric contractions.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectPotentiationen_US
dc.subjectPower outputen_US
dc.subjectRLC Phosphorylationen_US
dc.subjectskeletal muscleen_US
dc.titleReduced power output in skeletal muscles devoid of skMLCK: RLC phosphorylation contributes to peak performanceen_US
dc.typeElectronic Thesis or Dissertationen_US
dc.degree.nameM.Sc. Applied Health Sciencesen_US
dc.degree.levelMastersen_US
dc.contributor.departmentApplied Health Sciences Programen_US
dc.degree.disciplineFaculty of Applied Health Sciencesen_US


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