The acute effects of glycemic control on axonal excitability in human diabetic nerves.
OBJECTIVE
To investigate whether glycemic control is associated with reversible changes in axonal excitability in human diabetic nerves. It is known that voluntary contraction or compression ischemia alters nerve Na+/K+ pump activity, and axonal excitability changes due to the pump activity can be estimated by threshold tracking.


METHODS
Threshold, the current required to produce a compound muscle action potential 50% of maximum, was determined from the stimulus-response curve, and threshold changes produced by maximal voluntary contraction or ischemia were measured before and after insulin treatment in 10 diabetic patients.


RESULTS
Within 3 weeks of the start of treatment, the threshold changes became greater following voluntary contractions (+13+/-4% versus +23+/-5%; mean+/-SEM; p=0.04) and during ischemia (-5+/-2% versus -11+/-2%; p=0.04).


CONCLUSIONS
The extent of threshold fluctuation depends on multiple metabolic factors associated with diabetes such as decreased Na+/K+ ATPase activity, increased anaerobic glycolysis, and tissue acidosis, and nerve excitability can respond quickly to glycemic control in diabetic patients.
Kuwabara
Satoshi
S
Department of Neurology, Chiba University School of Medicine.
Ogawara
Kazue
K
Harrori
Takamichi
T
Suzuki
Yoshifumi
Y
Hashimoto
Naotake
N
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D001369:Axons / Q000502:physiology*; D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000097:blood / Q000503:physiopathology*; D004576:Electromyography; D004594:Electrophysiology; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy*; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D010525:Peripheral Nerves / Q000503:physiopathology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D001786:Blood Glucose; D007328:Insulin; D000254:Sodium-Potassium-Exchanging ATPase