engleski

Intra-axonal recording from large sensory myelinated axons: Demonstration of impaired membrane conductances in early experimental diabetes

Aim/hypothesis. Diabetic neuropathy is accompaneid by a range of positive (paresthaesia, dysesthaesia, pain) and negative (hypesthaesia and anesthaesia) neurological symptoms suggesting widespread alterations in axonal excitability. The nature and mechanisms underlying these alterations in axonal excitability are not well understood. the aim of these study was to exakmine the extent of changes in membrane properties of an identified neuronal structure - zhe large myelinated sensory axons in early experimental diabetes in rats. Methods. Intra-axonal microelectrode recordings from nerve in short terme streptozotocin - induced diabetes rats were used to studymembrane properties using standard current - clamp technique. Results. In addition, to decreased conduction velocity we found several differences in physiological properties of sensory axons from diabetic rats: decreased resting membrane potential, decreased potential amplitude associated with slower rate of rise and decrease in inward rectification associated with slight alteration in outwardly rectifying conductances indicating impaired potassium conductances. Conclusion/interpretation. These results extend previous indirect evidence that potassium and sodium ionic conductances, most notably the inward rectifier (IR, Ih) are altered in large sensory axons of diabetic rats. the depression of IR could underly clinical neurological findings in diabetic patients.

Diabetic neuropathy; streptozotocin; rats; sensory myelinated axons; intra-axonal recording; action potential; inward rectification

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