Exercise-induced alterations in skeletal muscle myosin heavy chain phenotype: dose-response relationship
JOURNAL OF APPLIED PHYSIOLOGY, cilt.86, sa.3, ss.1002-1008, 1999 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 86 Sayı: 3
- Basım Tarihi: 1999
- Doi Numarası: 10.1152/jappl.1999.86.3.1002
- Dergi Adı: JOURNAL OF APPLIED PHYSIOLOGY
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.1002-1008
- Anahtar Kelimeler: endurance exercise, muscle plasticity, fiber type, oxidative capacity, FAST-TWITCH MUSCLE, ENDURANCE EXERCISE, BIOCHEMICAL ADAPTATIONS, FIBER-TYPE, RAT, ISOFORMS, SLOW, TRANSITIONS, STIMULATION, INTENSITY
- Hacettepe Üniversitesi Adresli: Evet
Özet
This study investigated the effects of exercise training duration on the myosin heavy chain (MHC) isoform distribution in rat locomotor muscles. Female Sprague-Dawley rats (120 days old) were assigned to either a sedentary control group or to one of three endurance exercise training groups. Trained animals ran on a treadmill at similar to 75% maximal Og uptake for 10 wk (4-5 days/wk) at one of three different exercise durations (30, 60, or 90 min/day). Training resulted in increases (P < 0.05) in citrate synthase activity in the soleus and extensor digitorum longus in both the 60 and 90 min/day duration groups and in the plantaris (Pla) in all three exercise groups. All durations of training resulted in a reduction (P < 0.05) in the percentage of MHCIIb and an increase (P < 0.05) in the percentage of MHCIIa in the Pla. The magnitude of change in the percentage of MHCIIb in the Pla increased as a function of the training duration. In the extensor digitorum longus, 90 min of daily exercise promoted a decrease (P < 0.05) in percentage of MHCIIb and increases (P < 0.05) in the percentages of MHCI, MHCIIa, and MHCIId/x. Finally, training durations greater than or equal to 60 min resulted in an increase (P < 0.05) in the percentage of MHCI and a concomitant decrease (P < 0.05) in the percentage of MHCIIa in the soleus. These results demonstrate that increasing the training duration elevates the magnitude of the fast-to-slow shift in MHC phenotype in rat hindlimb muscles.