These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Mitochondrial function in intact skeletal muscle fibres of creatine kinase deficient mice.
    Author: Bruton JD, Dahlstedt AJ, Abbate F, Westerblad H.
    Journal: J Physiol; 2003 Oct 15; 552(Pt 2):393-402. PubMed ID: 14561823.
    Abstract:
    Creatine kinase (CK) has a central role in skeletal muscle, acting as a fast energy buffer and shuttle between sites of energy production (mitochondria) and consumption (cross-bridges and ion pumps). Unexpectedly, isolated fast-twitch skeletal muscle cells of mice deficient in both cytosolic and mitochondrial CK (CK-/-) are highly fatigue resistant during stimulation protocols that stress aerobic metabolism. We have now studied different aspects of mitochondrial function in CK-/- skeletal muscle. Intact, single fibres of flexor digitorum brevis (FDB) muscles were fatigued by repeated tetanic stimulation (70 Hz, 350 ms duration, duty cycle 0.14). Under control conditions, CK-/- FDB fibres were more fatigue resistant than wild-type fibres. However, after mitochondrial inhibition with cyanide, force declined markedly faster in CK-/- fibres than in wild-type fibres. The rapid force decline in CK-/- fibres was not due to decreased myoplasmic [Ca2+] during tetani (measured with indo-1), which in these fibres remained virtually constant during fatigue in the presence of cyanide. Intact, single fibres of highly oxidative soleus muscles were fatigued by repeated tetani (50 Hz, 500 ms duration, duty cycle 0.5). All CK-/- soleus fibres tested (n = 9) produced > 40 % force at the end of the fatiguing stimulation period (500 tetani), whereas force fell to < 40 % before 500 tetani in two of three wild-type fibres. Mitochondrial [Ca2+] (measured with rhod-2 and confocal microscopy) increased during repeated tetanic stimulation in CK-/- but not in wild-type FDB fibres. In conclusion, mitochondria and energy shuttling operate effectively in CK-/- fibres and this is associated with an increase in mitochondrial [Ca2+].
    [Abstract] [Full Text] [Related] [New Search]