Acute central respiratory effects of diazepam, its solvent and propylene glycol

Abstract

The effects of diazepam, its vehicle and propylene glycol on central respiratory activity recorded in the phrenic nerve was observed in anaesthetized paralysed dogs. Pao2 was greater than 24 kPa ftcO2 arterial pH and core temperature were maintained within narrow limits within the normal range. Diazepam 2 mg kg-1 caused an 80% reduction in phrenic nerve activity for more than 30 nun. The vehicle present in this dose caused only a transient insignificant change in phrenic activity, a second dose of vehicle equivalent to diazepam 5mgkg-1 caused a 40% reduction in activity which rapidly recovered. Propylene glycol in an amount in the vehicle of doses between 2 mg kg-1 and 20 mg kg-1 of diazepaM.Did not cause either depression of central respiratory activity or desynchronizaaon of this activity from the ventilation cycle, but reflexly evoked a small transient increase in activity. © 1982 The Macmillan Press Ltd.