Effect of diabetes on motor conduction velocity in different branches of the rat sciatic nerve.

Motor nerve conduction velocity was measured in six branches of the sciatic nerve in streptozotocin-diabetic rats. It was markedly reduced in nerves to the gastrocnemius, soleus, tibialis anterior, and extensor digitorum longus muscles. The branch to the plantaris muscle remained unaffected. In control rats none of these branches showed any evidence of conduction velocity maturation over the 2-month experimental period. Motor nerve conduction velocity to the interosseus muscles of the foot did show a normal maturation effect, which was halted by diabetes. We conclude that large-caliber motor fibers in mature nerves are particularly susceptible to diabetes.