Rescue of Hypoxia/Reoxygenation Induced Impaired Dilation in Rat Cerebral Arterioles

摘要

Cerebral arterioles were isolated, cannulated and their vasomotor responses to adenosine tri-phosphate (ATP) observed before and/or after hypoxia (PO_2< 5 mmHg) with rapid normoxic reoxygenation (H/RO). Reoxygenation resulted in a lasting vasoconstriction. Dilation to ATP was significantly decreased. Oxygen radial scavenger or calcium sensitive potassium channel openers restored dilation to ATP but not inhibition of nitric oxide synthase. H/RO directly impaired cerebral arteriolar regulation causing prolonged constriction and reduced dilation which could contribute to the hypoperfusion observed after ischemia/reperfusion and promote neuronal damage, possibly via production of reactive oxygen species (ROS) and subsequent inhibition of calcium activated potassium channels. ROS scavenging or potassium channel openers rescued the vessel response.