Peripheral electrophysiological parameters in mice treated with misonidazole.

The clinical use of the radiosensitizer misonidazole may be limited by the incidence of peripheral neuropathy reported following total doses in excess of 18 g. A recent report noted a decrease in nerve conduction velocity following a single i.p. injection of 1 mg/g misonidazole in mice. The present study was unable to confirm such changes when nerve conduction velocity measurements were made in situ or in isolated sural, tibial or median nerves of mice. Other electrophysiological parameters such as threshold, strength-duration curves, refractory time or the ability to carry high-frequency stimulation also showed no change. However, it was noted that a single administration of the radio-sensitizer produced a marked decrease in body temperature which persisted for at least 2 h after the elimination of the drug from the blood serum. The physiological response of reduction of body temperature may protect the mouse against the effect of the toxic chemical species involved in the induction of neurotoxicity.