Effects of sodium metavanadate on the electrical stimulation of sciatic nerve of toads (Bufo regularis)

Abstract

Introduction: Vanadium and its compounds have been documented to exert toxic effects on almost all systems in living organisms including cardiovascular, reproductive and nervous systems. In the nervous system however, toxicity assays have been on the brain and its structures with little information on its effects on peripheral nerves. This study was therefore conducted to examine the toxicity of vanadium in the peripheral nervous system. Methods: Vanadium as sodium metavanadate was used in the study. Fifteen toads (Bufo regularis) were randomly distributed into 3 groups (A-C); A served as control and was administered distilled water during the experiment, B were intraperitoneally (i.p.) administered with sodium metavanadate at 3 mg/kg while C were administered with sodium metavanadate at 5 mg/kg i.p. for 7 consecutive days. Nerve conduction was studied in isolated toad sciatic nerve-gastrocnemius muscle preparation following electrical stimulation. The recordings were obtained on a kymograph for each group. Results: The results showed significant (p<0.05) reduction in the peak amplitude of the action potential and an increase in the latency of the onset of the action potential at 5 mg/kg sodium metavanadate. Furthermore, an increased threshold stimulus voltage was also observed in group administered with 5 mg/kg sodium metavanadate. The values of these parameters in the 3 mg/kg sodium metavanadate group were not statistically different from the control group. Significance: The findings of this preliminary study suggest that vanadium at 5 mg/kg may result in decrease speed of impulse conduction which may be as a result of demyelination in the sciatic nerve.