Thermal sensitivity of contractile function in chain pickerel, Esox niger

Publisher Website
Google Scholar
Abstract
Maximum catalytic activity and thermal sensitivity of Mg2+–Ca2+ activated myofibrillar ATPase from either red or white muscle tissue of chain pickerel is unaffected by 4–6 weeks acclimation to temperatures of 5 or 25 °C. Arrhenius plots of myofibrillar ATPase activity from red muscle are linear over the entire range of assay temperatures (2–32 °C; Q10 = 3.3). Similar plots of white muscle ATPase activity show a pronounced discontinuity at approximately 10 °C and a much greater thermal sensitivity below this temperature (Q10 = 11.2) than above it (Q10 = 2.2). Thermal dependence of myofibrillar ATPase activity from white muscle does not accurately predict the effect of temperature upon contraction velocities of isolated white muscle fibers. Contraction velocity of single chemically skinned white muscle fibers was sevenfold less temperature sensitive than ATPase activity below the 10 °C transition and 1.6-fold less temperature sensitive above this temperature (Q10 (0–27 °C) = 1.6). Maximum Ca2+-activated tension development was particularly temperature independent (Q10 = 1.2), ranging from 14 ± 1.6 N/cm2 at 5 °C to 20.9 ± 2.1 N/cm2 at 25 °C. Power output chain pickerel muscle, a product of these two parameters (force × velocity), should therefore show a relatively low thermal dependence (Q10 < 2) over the normal range of habitat temperatures.

This publication has 14 references indexed in Scilit: