College of Science and Health Theses and Dissertations

Date of Award

Spring 6-14-2013

Degree Type


Degree Name

Master of Science (MS)



First Advisor

Jason Bystriansky, Ph.D.

Second Advisor

Elizabeth E. LeClair, Ph.D.

Third Advisor

Timothy Sparkes, Ph.D.


Rainbow trout, Oncorhynchus mykiss, are often recognized for their physiologically demanding migration patterns. Shifts in relative expression of specific Na+/K+-ATPase isoforms have been identified during salinity acclimation and similar changes in expression may also occur in response to other physiological challenges. The Na+/K+- ATPase plays a crucial role in the maintenance of membrane potential and excitability during muscle contraction through prompt restoration of sodium and potassium gradients. Additionally, a tissue-specific isoform (α2) has been identified within skeletal muscle, with localized expression conserved across multiple species but the specific function is unknown. This study examined mRNA expression of α isoforms in hatchery-reared juvenile rainbow trout in response to aerobic (3 BL/s) and anaerobic (8 BL/s, near Ucrit) swimming challenges, including an analysis of oxidative vs. glycolytic muscle types and potential training effects involving isoform expression. We observed differential regulation of Na+/K+-ATPase isoforms between red and white muscle, with significant transcriptional upregulation in red muscle and no shifts in white muscle or heart tissues. Generally, mRNA increases in red muscle were greatest following 4 days of training, with equivalent or larger increases after 4 days of recovery. This trend was seen after both burst and sustained swimming regimens; however, high-intensity swimming induced greater upregulation. During training, burst swimming near Ucrit significantly increased mRNA levels for all α isoforms measured (1.5-fold for α1c, 2−fold for α2, and 2.5-fold for α3) while swimming at 3 BL/s resulted in upregulation only in α2. Repeated burst swimming reduced plasma osmolality and chloride, persisting into recovery, suggesting intense exercise simultaneously compromises osmoregulatory function during periods of high-energy demand.

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Biology Commons