|
| ![]() |
|
||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online October 7, 2008
Journal of Experimental Biology 211, 3237-3248 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.019257
Differential recovery from exercise and hypoxia exposure measured using 31P- and 1H-NMR in white muscle of the common carp Cyprinus carpio
Department of Zoology, The University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
* Author for correspondence (e-mail: jrichard{at}zoology.ubc.ca)
Accepted 15 July 2008
Phosphocreatine (PCr) was reduced to equivalent levels in carp white muscle
by high-intensity exhaustive exercise and exposure to hypoxia at 15°C and
25°C in order to assess the influence of intracellular pH
(pHi), temperature and lactate levels on PCr recovery in
vivo. High-intensity exercise resulted in a significantly lower
pHi compared with hypoxia exposure and the rate of PCr depletion
and tissue acidification during hypoxia exposure was significantly higher in
carp held at 25°C compared with those at 15°C. During recovery, PCr
and pHi returned towards normoxia/resting levels at a faster rate
following hypoxia exposure than after exercise. The lower pHi in
exercised carp caused a greater perturbation to cellular energy status
(assessed as the free energy of ATP hydrolysis;
fG') and
resulted in a higher [ATP]/[ADPfree] ratio, which may limit
mitochondrial ATP production and contribute to the slower recovery from
exercise compared with recovery from hypoxia exposure. Rates of recovery from
exercise and hypoxia exposure were not affected by acclimation temperature (15
and 25°C), suggesting that the processes involved in acclimation
compensate for the Q10 effects of temperature on metabolic
processes. Finally, using a dual 31P-NMR and 1H-NMR
analysis technique, we demonstrated that the greater tissue acidification
observed after high-intensity exercise compared with hypoxia exposure occurred
at similar white muscle lactate concentrations.
Key words: fish, muscle energetics, phosphorylation, potential, recovery, temperature
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?