Motor and sensory conduction in peripheral nerves of unanaesthetized streptozotocin diabetic and normal rats during ischemia.

ABSTRACT

Motor nerve conduction velocities (MNCVs) of ventral peripheral tail nerves of unanaesthetized streptozotocin diabetic rats were examined in comparison to age matched normal rats under normal and ischemic conditions. A miniature blood pressure cuff was applied to the base of the tail and was adjusted to provide complete vascular occlusion for 30 min. MNCVs were recorded during ischemia and in the post-ischemic period. MNCVs were markedly reduced during ischemia in normal rats but were unchanged in diabetic rats. Conversely, the sensation of heat induced pain was retained to an equal extent in normal and diabetic rats during ischemia states. The abnormal resistance to ischemia of MNCV of peripheral nerves is an early and sensitive index of nerve dysfunction and precedes slowing of MNCV in diabetic rats. The results suggest that initial peripheral nerve abnormalities in diabetic rats may be related to biochemical changes rather than axonopathy and may have heuristic significant for clinical diabetic neuropathy.