[Oxygen tension in the skeletal muscles of rats adapted to the cold]

In control and cold-adapted rats the oxygen tension (pO2) was measured polarographically in the fast (gastrocnemic) and slow (soleus) muscles before and after blocking of beta-adrenoreceptors or the denervation of the muscle. The beta-adrenoreceptor blockade decreases the pO2 in both types of muscles in the control group of rats, whereas in cold-adapted rats the decrease of pO2 both types of muscles in the control group of rats, whereas in cold-adapted rats the decrease of pO2 is less pronounced in the coleus and remains unchanged in the gastrocnemic muscle. The sciatic nerve dissection augments the pO2 in both muscles, the increase being larger in cold-adapted rats as compared to the control group. It seems that the dependence of the oxygenation processes in muscles on nervous control and on the state of beta-adrenoreceptors increases during adaptation to cold mainly in the slow muscles.