Comparison of Local Blood Flow and Oxygen Availability at the Same Locus in the Ischemic Gerbil Brain

Oxygen availability (O2 a) and local cerebral blood flow (CBF) as H2 clearance were measured at the same point, taking advantage of the sensitivity of the platinized platinum electrode to both H2 and O2 in gerbils following ischemia made by transient bilateral carotid artery ligations. Both O2 a and CBF were zero during carotid ligation. During postischemic reperfusion there was a qualitative correlation between the two, with a tendency for the O2 a recovery to be less than that of CBF in the first hour and greater in the second hour. These differences in the time course of O2 a and cerebral blood flow may be accounted for by altered oxygen consumption in relation to tissue perfusion, or by altered oxygen sensitivity of the electrode. The results demonstrated the feasibility of making oxygen and flow measurements at the same point in tissue.