Abstract
To examine the possibility that the dexmedetomidine-induced cerebral vasoconstriction deteriorates ischemic brain damage, we administered dexmedetomidine during transient focal cerebral ischemia in rats. Rats received intravenous infusions of dexmedetomidine at 0.1μg·kg-1·min-1, and 1μg·kg-1·min-1 during cerebral ischemia induced by the occlusion of the middle cerebral artery with a nylon suture. Further, 5mg·kg-1 of yohimbine combined with dexmedetomidine were also given during the cerebral ischemia. Cerebral infarction was detected in rats receiving infusions of dexmedetomidine at 0.1μg·kg-1·min-1 and 1μg·kg-1·min-11. Cerebral infarct volume was significantly larger in rats receiving dexmedetomidine infusion at 1μg·kg-1·min-1 than that of rats receiving at 0.1μg·kg-1·min-1. Treatment with yohimbine significantly decreased the dexmedetomidine-induced infarct volume by 84%. Therefore, it is suggested that the infusion of high-dose dexmedetomidine aggravates ischemic brain damage following focal cerebral ischemia in rats via the activation of alpha-2 adrenoceptor.
