Аннотация:Cerebral activation will increase cerebral blood flow (CBF) and cerebral glucose uptake (CMR glc ) more than it increases cerebral uptake of oxygen (CMR O2 ). To study this phenomenon, we present an application of the Kety–Schmidt technique that enables repetitive simultaneous determination of CBF, CMR O2 , CMR glc and CMR lac on awake, non‐stressed animals. After constant intravenous infusion with 133 Xenon, tracer infusion is terminated, and systemic arterial blood and cerebral venous blood are continuously withdrawn for 9 min. In this paper, we evaluate if the assumptions applied with the Kety–Schmidt technique are fulfilled with our application of the method. When measured twice in the same animal, the intra‐individual variation for CBF, CMR O2 , and CMR glc were 10% (SD: 25%), 8% (SD: 25%), and 9% (SD: 28%), respectively. In the awake rat the values obtained for CBF, CMR O2 and CMR glc were 106 mL [100 g] −1 min −1 , 374 μmole [100 g] −1 min −1 and 66 μmole [100 g] −1 min −1 , respectively. The glucose taken up by the brain during wakefulness was fully accounted for by oxidation and cerebral lactate efflux. Anaesthesia with pentobarbital induced a uniform reduction of cerebral blood flow and metabolism by ≈40%. During halothane anaesthesia CBF and CMR glc increased by ≈50%, while CMR O2 was unchanged.
