Biology subjects

Bishop, D. J.

Publications and source records attributed to Bishop, D. J..

20 records · Page 2Linked to original sources

bioRxiv2017

Post-exercise cold-water immersion increases Na+,K+-ATPase α2-isoform mRNA content in parallel with elevated Sp1 expression in human skeletal muscle

We investigated the effect of a session of sprint-interval exercise on the mRNA content of NKA isoforms (1-3, {beta}1-3) and FXYD1 in human skeletal muscle. To explore some of the cellular stressors involved in this regulation, we evaluated the association between these mRNA responses and those of the transcription factors Sp1, Sp3 and HIF-1. Given cold exposure perturbs muscle redox homeostasis, which may be one mechanism important for increases in NKA-isoform mRNA, we also explored the effect of post-exercise cold-water immersion (CWI) on the mRNA responses. Muscle was sampled from nineteen men before (Pre) and after (+0h, +3h) exercise plus passive rest (CON, n=10) or CWI (10{degrees}C; COLD, n=9). In COLD, exercise increased NKA2 and Sp1 mRNA (+0h, p<0.05). These genes remained unchanged in CON (p>0.05). In both conditions, exercise increased NKA1, NKA{beta}3 and HIF-1 mRNA (+3h; p <0.05), decreased NKA{beta}2 mRNA (+3h; p<0.05), whereas NKA3, NKA{beta}1, FXYD1 and Sp3 mRNA remained unchanged (p>0.05). These human findings highlight 1) sprint-interval exercise increases the mRNA content of NKA 1 and {beta}3, and decreases that of NKA {beta}2, which may relate, in part, to exercise-induced muscle hypoxia, and 2) post-exercise CWI augments NKA2 mRNA, which may be associated with promoted Sp1 activation.

physiology↗

bioRxiv2017

Ribosome biogenesis adaptation and mTORC1 signalling in human skeletal muscle following concurrent training compared with resistance training alone

1.Combining endurance training with resistance training (RT) may attenuate skeletal muscle hypertrophic adaptation versus RT alone; however, the underlying mechanisms are unclear. We investigated changes in markers of ribosome biogenesis, a process linked with skeletal muscle hypertrophy, following concurrent training versus RT alone. Twenty-three males underwent eight weeks of RT, either performed alone (RT group, n = 8), or combined with either high-intensity interval training (HIT+RT group, n = 8), or moderate-intensity continuous training (MICT+RT group, n = 7). Muscle samples (vastus lateralis) were obtained before training, and immediately before, 1 h and 3 h after the final training session. Training-induced changes in basal expression of the 45S ribosomal RNA (rRNA) precursor (45S pre-rRNA), and 5.8S and 28S mature rRNAs, were greater with concurrent training versus RT. However, during the final training session, RT further increased both mTORC1 (p70S6K1 and rps6 phosphorylation) and 45S pre-rRNA transcription-related signalling (TIF-1A and UBF phosphorylation) versus concurrent training. These data suggest that when performed in a training-accustomed state, RT induces further increases mTORC1 and ribosome biogenesis related signalling in human skeletal muscle versus concurrent training; however, changes in ribosome biogenesis markers were more favourable following a period of short-term concurrent training versus RT performed alone.

physiology↗