Early Diazepam Treatment Following Unilateral Labyrinthectomy Does Not Impair Vestibular Compensation of Spontaneous Nystagmus in Guinea Pig*

Abstract

Diazepam and other benzodiazepines are sometimes used to alleviate vertigo and dizziness following labyrinthine surgery in humans. While the results of some previous studies have suggested that the administration of diazepam and other CNS depressant drugs following unilateral labyrinthectomy (UL) may impair the vestibular compensation process, the available evidence is unclear. The objective of the present experiment was to examine the effects of multiple injections of a high dose of diazepam (that is, 10 mg/kg i.p.) 30 min before and following UL (10 h or 10 and 20 h) on the static symptom, spontaneous ocular nystagmus (SN), in guinea pigs. Although diazepam-treated animals exhibited consistently lower average SN frequency compared to vehicle controls. neither SN frequency nor its rate of compensation were significantly different between the 2 groups. The time to complete SN compensation was also similar for the 2 groups, as estimated from the x intercepts derived from a linear regression analysis. These results suggest that even high doses of diazepam before and following UL do not result in an impairment of compensation of SN in guinea pig.