Regional Differences in the Cerebrovascular Reserve Following Acute Global Ischemia in Rabbits

Summary

The changes of the blood flow velocity in different cerebral arteries under normal and postischemic conditions were investigated in order to evaluate cerebrovascular reserve capacity after the brain ischemia. The experiments were carried out in rabbits. Administration of acetazolamide (Diamox) of 20 mg/kg was performed in all experimental animals and the blood flow velocity in the middle cerebral artery (MCA) and the basilar artery (BA) was measured using the transcranial Doppler sonography. In the control group of animals the intravenous administration of Diamox caused significant increase of the blood flow velocity in the MCA and the BA. In the second group of animals subjected to the acute global ischemia (occlusion of two vessels + hypotension) of 10 min duration prior to the Diamox administration, no increase of the blood flow velocity in the MCA was observed parallel with an increase in the BA. In some animals there was a decrease in the blood flow velocity in MCA. This could be a consequence of stealing phenomenon, as an increase of cerebral blood flow in the posterior fossa compartment, at the cost of the supratentorial circulation. Identification of the areas damaged after the brain ischemia was performed by the 2,3,5-triphenyltetrazoliumchloride (TTC) staining technique. This revealed more pronounced ischemic lesions in the cerebral cortex in comparison to the region of the basal ganglia.