Journal of Applied Physiology, Vol 47, Issue 5 1018-1024, Copyright © 1979 by American Physiological Society
Interaction of hyperoxia and blood flow during fatigue of canine skeletal muscle in situ
J. K. Barclay, C. M. Boulianne, B. A. Wilson and S. J. Tiffin
Right and left gastrocnemius-plantaris muscle preparations in 20 dogs
anesthetized with pentobarbital sodium were used to investigate the effect
of hyperoxia on tension maintenance. Muscles were stimulated via the
sciatic nerve for 20 min at 60 200-ms tetanic contractions/min (10
impulses/contraction). Direct muscle stimulation after the experimental
period resulted in no significant change in tension. In control experiments
the tension developed by the right or left muscles over the 20 min was not
different. The tension developed by muscles perfused with hyperoxic blood
decreased 14% after 20 min, whereas tension in the normoxic muscles
decreased 35%. Blood flow in the hyperoxic muscles was significantly higher
at 20 min (P less than 0.05). Pump perfusion of one of a pair of normoxic
muscles resulted in a tension decrease of 13% in the pump-perfused muscles,
whereas tension in the control muscles decreased 34%. Tension maintenance
was flow dependent. The effect of hyperoxia could be mediated through the
involvement of oxygen in the long-term control of muscle blood flow.
