Ischemia-induced development of cerebral edema in awake and anesthetized gerbils.

Abstract

General anesthesia is often used to immobilize experimental animals prior to the induction of cerebral ischemia. However, anesthetics are known to alter many of the biochemical and physiological parameters used for the assessment of stroke-induced brain damage. We examined the effects of bilateral carotid artery ligations on mortality and the development of cerebral edema in unanesthetized gerbils. We found that increasing the length of the ischemic episode resulted in increased mortality, both during the ischemic period and during cerebral reperfusion. The duration of the ischemic episode was also correlated with the rate and degree of the development of cerebral edema. Both of these estimates of ischemia-induced brain damage were significantly reduced by the pretreatment of the animals with pentobarbital. Based on the variable effects of different anesthetics on CNS activities, and the observed effects of barbiturate anesthesia on ischemia-induced mortality and edema development in the present model, we suggest that it may be inappropriate to anesthetize experimental animals when investigating certain aspects of stroke-induced brain damage.