REDUCED LACTATE TRANSPORT IN DENERVATED RAT SKELETAL-MUSCLE

The purpose of this study was to investigate the effect of the neural regulation of contractile activity on lactate transport in skeletal mu scle. Contractile activity of the rat soleus muscle was abolished by d enervating the hindlimb muscles in one leg (3 days) while the sham-ope rated contralateral hindlimb muscles served as a control. Three days a fter surgery, lactate transport into the soleus muscle was measured in vitro, using incubated soleus muscle strips. Lactate uptake by the de nervated soleus muscle was reduced compared with control (P < 0.05). T he diffusive component of lactate transport was unaltered by denervati on (P > 0.05). These results translated into a reduction in lactate ca rrier-mediated transport capacity (-68%) in the denervated soleus (P < 0.05). These studies indicate that loss of contractile activity resul ts in a decrement of lactate transport, which is probably due to a red uction in the number of lactate carriers in the sarcolemma. Our result s suggest that the inherent activity of the muscle is important in mai ntaining the lactate transport system.