Effects of Hypoxia on the Contractile and Electrical Responses of Chick Embryo Skeletal Muscles in the Last Third of Embryogenesis

Autor: I. V. Kubasov, T. A. Alekseeva, M. V. Nechaeva
Rok vydání: 2015
Předmět:
Zdroj: Neuroscience and Behavioral Physiology. 45:894-901
ISSN: 1573-899X
0097-0549
DOI: 10.1007/s11055-015-0163-z
Popis: Developmental changes in the contractile and electrical responses of isolated fast (tibialis anterior) and slow (soleus) muscles from chick embryo (16–20 days of embryonic development) were studied, as were the effects of hypoxia on them. Normalized contractile response forces for tibialis anterior were significantly greater than those for soleus. On days 16–17 of embryogenesis, soleus and tibialis anterior muscle fibers showed slow decaying oscillation waves of excitation, while extracellular recording identified propagating action potentials in 20% of the tibialis anterior muscle fibers studied. By day 20 of embryonic development, the number of muscle fibers able to generate action potentials in fast muscles approached 100%. In slow muscles, this value was close to 50%. Hypoxia induced a reduction in the strength of the contractile responses of muscles at all study time points during the incubatory development of embryos, but was not found to have any effect on the magnitude of the contractile response evoked by caffeine. These results lead to the conclusion that in these conditions, hypoxia has no influence on the functional state of ryanodine receptors. Muscles treated with insulin and ouabain showed significant reductions in the sensitivity of contractile responses to hypoxia. It is suggested that the effects of hypoxia involve an active role for membrane Na+,K+-ATPase.
Databáze: OpenAIRE
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