Increased fatigue resistance linked to Ca²⁺-stimulated mitochondrial biogenesis in muscle fibres of cold-acclimated mice

Abstract

Mammals exposed to a cold environment initially generate heat by repetitive muscle activity (shivering).

PGC-1α Mediated Muscle Aerobic Adaptations to Exercise, Heat and Cold Exposure

“…In addition, the decrement in force was 40% greater in the control compared with the cold acclimatised mice during stimulated repetitive contractions, indicating improved fatigue resistance following cold acclimatisation (Bruton et al, 2010). It was also found that basal muscle Ca 2+ content was 50% higher, while no indication of AMPK phosphorylation were evident in the cold acclimatised mice compared with controls (Bruton et al, 2010). As such, while it is possible that Ca 2+ , in addition to β-adrenergic mechanisms could be involved in cold-induced PGC-1α and mitochondrial biogenesis, targets downstream of Ca 2+ signalling have yet to be elucidated (Fig.…”

“…However, in this study it was possible that mitochondrial biogenesis were the result of muscle contractions associated with shivering thermogenesis. However, a more recent study has observed a 50% increase in PGC-1α protein expression as well as increased CS and β-HAD activities following cold acclimatisation (18°C for 4 wk followed by 4°C for 4-5 wk's) in mice flexor digitorum brevis muscles, which do not partake in the shivering response (Bruton et al, 2010). In addition, the decrement in force was 40% greater in the control compared with the cold acclimatised mice during stimulated repetitive contractions, indicating improved fatigue resistance following cold acclimatisation (Bruton et al, 2010).…”

“…However, a more recent study has observed a 50% increase in PGC-1α protein expression as well as increased CS and β-HAD activities following cold acclimatisation (18°C for 4 wk followed by 4°C for 4-5 wk's) in mice flexor digitorum brevis muscles, which do not partake in the shivering response (Bruton et al, 2010). In addition, the decrement in force was 40% greater in the control compared with the cold acclimatised mice during stimulated repetitive contractions, indicating improved fatigue resistance following cold acclimatisation (Bruton et al, 2010). It was also found that basal muscle Ca 2+ content was 50% higher, while no indication of AMPK phosphorylation were evident in the cold acclimatised mice compared with controls (Bruton et al, 2010).…”

“…Moreover, there is emerging evidence highlighting the potential of these modalities to enhance mitochondrial adaptations either independently or in response to training. For instance, in studies using cell culture and animal models, mitochondrial biogenesis has shown to be up-regulated following both heat and cold exposures through PGC-1α dependant mechanisms similar to that observed following exercise (Bruton et al, 2010;Liu & Brooks, 2012;Puigserver et al, 1998;Tamura et al, 2014;Wu et al, 1999). However, when administered following exercise, both heat and cold interventions have demonstrated contradictory results, with some studies showing beneficial, while others detrimental effects on PGC-1α and/or muscle aerobic performance (Ihsan et al, 2014;Slivka et al, 2013;Slivka et al, 2012;Tamura et al, 2014;Yamane et al, 2006).…”

“…In this regard, it is puzzling that there has been very little research investigating muscle oxidative adaptations in response to cold exposure using in vivo models (Bruton et al, 2010;Walters & Constable, 1993;Wijers et al, 2008;Wijers et al, 2011). In an early study, a 22 to 23% increase in CS activity, indicating an increase in mitochondrial content was observed in rat skeletal muscles following daily (5 days•wk -1 ) cold water immersion (60 min at 20°C) over a 17 to 19 wk period (Walters & Constable, 1993).…”