Focal Cerebral Ischaemia in the Rat: 2. Regional Cerebral Blood Flow Determined by [ 14 C]Iodoantipyrine Autoradiography following Middle Cerebral Artery Occlusion

Local cerebral blood flow has been measured by quantitative autoradiography, employing [¹⁴C]iodoantipyrine as tracer, in rats killed half an hour after occlusion of the middle cerebral artery. The results were compared with pattern of local cerebral blood flow (CBF) in sham-operated rats and with neuropathological findings. In every animal there was a profound reduction (to 13% of control levels) in blood flow in the neocortex previously supplied by the occluded artery. The level of blood flow in the areas in which ischaemic brain damage occurred was 0.24 ±0.03 ml g⁻¹ min⁻¹ (mean ± SEM). This level of CBF is considerably greater than that reported following a similar surgical procedure in cats and primates. Moderate reductions in blood flow were also seen outside the territory of the occluded artery and in parts of the opposite hemisphere. Absolute increases in blood flow (hyperaemia) were seen only in the substantia nigra and globus pallidus ipsilateral to the occlusion. It is suggested that this finding and the reductions in blood flow outside the territory of the middle cerebral artery are reflections of alterations in neuronal function and metabolic activity secondary to the ischaemic lesion.