Effects of Dexmedetomidine on Microregional O2 Balance during Reperfusion after Focal Cerebral Ischemia

Background This study was performed to determine whether there is an association between microregional O2 balance and neuronal survival in cerebral ischemia–reperfusion using dexmedetomidine, an α2 -adrenoreceptor agonist and a sedative. Methods Rats were subjected to 1 hour middle cerebral artery occlusion and a 2-hour reperfusion. During reperfusion, normal saline (n = 14) or dexmedetomidine 1 μg/kg/minute (n = 14) was infused intravenously. At 2 hours of reperfusion, regional cerebral blood flow using14 C-iodoantipyrine autoradiography, microregional arterial and venous (20-60 μm in diameter) O2 saturation (SvO2 ) using cryomicrospectrophotometry, and the size of cortical infarction were determined. Results Ischemia–reperfusion decreased microregional SvO2 (52.9 ± 3.7% vs. 61.1 ± .6%, P