Effects of xenon on cerebral flood flow and cerebral glucose utilization in rats

Background: The effects of xenon inhalation on mean and local cerebral bloo d flow (CBF) and mean and local cerebral glucose utilization (CGU) were inv estigated using iodo-[C-14]antipyrine and [C-14]deoxyglucose autoradiograph y, Methods: Rats were randomly assigned to the following groups: conscious con trols (n = 12); 30% (n = 12) or 70% xenon (n = 12) for 45 min for the measu rement of local CBF and CGU; or 70% xenon for 2 min (n = 6) or 5 min (n = 6 ) for the measurement of local CBF only. Results: Compared with conscious controls, steady state inhalation of 30 or 70% xenon did not result in changes of either local or mean CBF. However, mean CBF increased by 48 and 37% after 2 and 5 min of 70% xenon short inhal ation, which was entirely caused by an increased local CBF in cortical brai n regions. Mean CGU determined during steady, state 30 or 70% xenon inhalat ion remained unchanged, although local CGU decreased in 7 (30% xenon) and 1 8 (70% xenon) of the 40 examined brain regions. The correlation between CBF and CGU in 40 local brain structures was maintained during steady state in halation of both 30 and 70% xenon inhalation, although at an increased slop e at 70% xenon. Conclusion: Effects of 70% xenon inhalation on CBF In rats are time-depende nt. During steady state xenon inhalation (45 min), mean values of CBF and C GU do not differ from control values, and the relation of regional CBF to C GU is maintained, although reset at a higher level.