Effects of Vitamin B complex in functional changes of the peripheral nerves of alloxan-induced diabetic rats

Abstract

Neurophysiological properties of the peripheral nerves of alloxan-induced diabetic rats and effects of vitamin B complex (V) were studied. Alloxan monohydrate was administered to Wistar (38 mg/kg, i.v.) and Sprague-Dawley (SD, 45 mg/kg, i.v.) rats. In Wistar diabetic rats (blood sugar level: more than 400 mg/dl for 6-8 weeks), nerve potentials with 2 peaks were recorded from the tibial and peroneal nerves. The late component had a higher threshold, longer time of recovery from excitation and slower conduction velocities. Large doses of V (B₁: 100, B₆: 100 and B₁₂: 1 mg/kg, i.p.) administered daily until the experiment inhibited the appearance of the late component. In SD diabetic rats(the same blood sugar content for 6 ?? 8 months), the ventral root potentials had a longer duration, higher threshold and longer time of recovery from excitation. In V administered rats, particularly along with insulin, these changes were prevented. Most efferent fibers of non-treated rats had a refractory period of less than 3.0 msec. The number of fibers with this refractory period was greatly reduced in the diabetic rats. Although rats administered each component of V₁₀₀ and V₅₀ had efferent fibers with similar refractory periods to that of rats in A-S group, those administered V₁₀₀ had efferent fibers with significantly shorter refractory periods. Thus, efferent fibers seem to be more sensitive than the afferent ones at the early stages of the long term diabetic state and a large dose of V, particularly along with insulin, depressed these changes.