Temperature- and exercise-induced gene expression and metabolic enzyme changes in skeletal muscle of adult zebrafish (Danio rerio)

J Physiol. 2006 Dec 1;577(Pt 2):739-51. doi: 10.1113/jphysiol.2006.119032. Epub 2006 Sep 21.


Both exercise training and cold acclimatization induce muscle remodelling in vertebrates, producing a more aerobic phenotype. In ectothermic species exercise training and cold-acclimatization represent distinct stimuli. It is currently unclear if these stimuli act through a common mechanism or if different mechanisms lead to a common phenotype. The goal of this study was to survey responses that represent potential mechanisms responsible for contraction- and temperature-induced muscle remodelling, using an ectothermic vertebrate. Separate groups of adult zebrafish (Danio rerio) were either swim trained or cold acclimatized for 4 weeks. We found that the mitochondrial marker enzyme citrate synthase (CS) was increased by 1.5x in cold and by 1.3x with exercise (P<0.05). Cytochrome c oxidase (COx) was increased by 1.2x following exercise training (P<0.05) and 1.2x (P=0.07) with cold acclimatization. However, only cold acclimatization increased beta-hydroxyacyl-CoA dehydrogenase (HOAD) compared to exercise-trained (by 1.3x) and pyruvate kinase (PK) relative to control zebrafish. We assessed the whole-animal performance outcomes of these treatments. Maximum absolute sustained swimming speed (Ucrit) was increased in the exercise trained group but not in the cold acclimatized group. Real-time PCR analysis indicated that increases in CS are primarily transcriptionally regulated with exercise but not with cold treatments. Both treatments showed increases in nuclear respiratory factor (NRF)-1 mRNA which was increased by 2.3x in cold-acclimatized and 4x in exercise-trained zebrafish above controls. In contrast, peroxisome proliferator-activated receptor (PPAR)-alpha mRNA levels were decreased in both experimental groups while PPAR-beta1 declined in exercise training only. Moreover, PPAR-gamma coactivator (PGC)-1alpha mRNA was not changed by either treatment. In zebrafish, both temperature and exercise produce a more aerobic phenotype, but there are stimulus-dependent responses (i.e. HOAD and PK activities). While similar changes in NRF-1 mRNA suggest that common responses might underlie aerobic muscle remodelling there are distinct changes (i.e. CS and PPAR-beta1 mRNA) that contribute to specific temperature- and exercise-induced phenotypes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Hydroxyacyl CoA Dehydrogenases / metabolism
  • Acclimatization / physiology*
  • Animals
  • Citrate (si)-Synthase / metabolism
  • Cold Temperature*
  • Electron Transport Complex IV / metabolism
  • Eye Proteins / metabolism
  • Gene Expression Regulation, Enzymologic*
  • Muscle Fatigue
  • Muscle, Skeletal / enzymology*
  • Muscle, Skeletal / metabolism
  • Nuclear Respiratory Factor 1 / metabolism
  • Peroxisome Proliferator-Activated Receptors / metabolism
  • Phenotype
  • Physical Conditioning, Animal / physiology*
  • Polymerase Chain Reaction
  • Pyruvate Kinase / metabolism
  • RNA, Messenger / metabolism
  • Time Factors
  • Zebrafish / metabolism*
  • Zebrafish Proteins / metabolism*


  • Eye Proteins
  • NRF1 protein, zebrafish
  • Nuclear Respiratory Factor 1
  • Peroxisome Proliferator-Activated Receptors
  • RNA, Messenger
  • Zebrafish Proteins
  • 3-Hydroxyacyl CoA Dehydrogenases
  • Electron Transport Complex IV
  • Citrate (si)-Synthase
  • Pyruvate Kinase