Influence of magnesium sulphate on evoked activity of rat brain after exposure to short-term hypoxia.

Abstract

Young Wistar rats (aged 12, 25 and 35 days) were exposed to short-term (60 min) hypobaric hypoxia of 41 kPa. Cortical afterdischarges (ADs) were evoked by repeated direct stimulation of the sensorimotor cortex and the duration of ADs was monitored to examine the influence of magnesium sulphate injection (0.3 g/kg b.w.). In 12-day-old hypoxia-exposed rats, an increase of the mean duration of ADs after the repeated stimulation appeared. This effect was prevented by magnesium administration. In 25- and 35-day-old rats exposed to hypoxia a shortening of ADs was registered but no specific effect of magnesium sulphate pretreatment was observed. The brain susceptibility and ability to terminate evoked seizures is discussed.