2001 Volume 12 Issue 4 Pages 297-302
This paper describes the experiments of cerebral venous circulation disorders (CVCDs) using rat photochemical cortical vein occlusion and information. Male Wistar rats were used. Cortical veins occlusion was induced by photochemical activation under general anesthesia. We examined changes of the cerebral venous flow pattern by fluorescence angiography, regional cerebral blood flow (rCBF) measured at 25 locations assessed by laser Doppler メscanningモ technique and histology 24 hours after surgery. We performed the following experiments; experiment-1: the effect of brain compression under cortical vein occlusion, experiment-2: the effect of age on cortical vein occlusion, experiment-3: CBF autoregulation in asymptomatic cortical vein occlusion. As results, (experiment-1): We demonstrated that, compared with vein occlusion or brain compression alone, the accumulated episode caused severe ischemia and increased the vulnerability of the tissue damage in the rat brain.(experiment-2): The results demonstrated an age-related increase in rate and size of venous infarction following vein occlusion, suggesting that the greater vulnerability to CVCDs in the aged brain might be attributed to early and extensive hypoperfusion of circumscribed brain areas drained by the occluded vein. (experiment-3): Autoregulatory capacity of CBF is influenced subsequent to vein occlusion, leaving surviving brain tissue partly susceptible to blood pressure change.
In conclusions, CVCDs manifest itself via additional pathways, i.e. brain compression, blood pressure decrease, and in old patients, even under conditions where the vein occlusion itself does not cause brain damage.
