Sensitivity and behavior of muscle spindles to systemic arterial hypoxia.

Abstract

SummaryThe effects of systemic arterial hypoxia on the afferent discharge of muscle spindles has been studied. In 48 primary spindle afferents, reductions of arterial oxygen tensions to approximately 80 mm Hg had no effect. Reduction of O2 tensions to approximately 45 mm Hg had no depressing effect in 41 of 48 spindle afferents whereas oxygen tensions of approximately 23 mm Hg abolished activity in all spindle afferents. High-frequency discharge from primary afferents known to be gastrocnemius-soleus spindles were not observed at the oxygen levels used.