Reversible and irreversible nodal dysfunction in diabetic neuropathy.

Area of Science:

• Neuroscience
• Diabetology
• Cellular Physiology

Background:

• Diabetic nerve dysfunction presents as acute reversible or chronic poorly reversible conditions.
• The link between biochemical, neuroanatomical, and nodal membrane function abnormalities in diabetes remains unclear.

Purpose of the Study:

• To investigate the mechanisms of diabetic nerve dysfunction in BB-rats.
• To correlate metabolic and structural defects with nodal membrane function in diabetic peripheral nerves.

Main Methods:

• Nodal clamp examinations were performed on the sciatic nerve of diabetic BB-rats.
• Action potentials, Na+ permeability, and Na+ gradient were assessed with increasing diabetes duration.

Main Results:

• Diabetes duration correlated with reduced nodal action potentials, decreased Na+ permeability, and diminished Na+ gradient.
• Insulin therapy reversed these defects in short-term diabetic rats but not in long-term ones.
• Long-term defects were associated with irreversible axoglial dysjunction.

Conclusions:

• Acute diabetic neuropathy involves reversible (Na+ + K+)-ATPase defects.
• Chronic diabetic neuropathy is characterized by poorly reversible nodal dysfunction and axoglial dysjunction.
• These findings highlight the progressive and potentially irreversible nature of nerve damage in long-standing diabetes.