In previous work, we observed that sciatic nerve trunks of rats exposed to epineurial ET developed transient dose-dependent endoneurial ischemia that might be associated with reversible motor conduction block. In the present study, we explored the possibility that ET ischemia might selectively damage axons of diabetic nerve trunks. In diabetic rats, but not controls, ET ischemia damaged a large proportion of sciatic axons, predicted in each instance by focal motor conduction block across the site of ET application and eventual loss of distal motor nerve excitability. Part of the susceptibility to ET in diabetes was accounted for by more intense and prolonged vasoconstriction.
Diabetic nerves are selectively susceptible to ET-mediated ischemia.