| Co-Investigator(Kenkyū-buntansha) |
SAWADA Tohru NCVC,Dept. of Cerebrovascular Diseases, direrctor, 脳血管内科, 部長
YAMAGUCHI Saburo NCVC,Dept. of Vascular Physiology, researcher, 脈管生理部, 室長 (00182436)
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| Research Abstract |
Cerebral microcirculatory hemodynamic changes were investigated during cerebral microvascular occlusion, based on an intravital microscopic observation of the pial microcirculation in cat and rats. The animals were anesthetized with pentobarbital sodium and mechanical ventilated. After craniotomy, a closed cranial window was prepared. We made a direct observation of the microcirculation on the cerebrocortical surface using a fluorescence videomicroscopic system. FITC-labeled red cells and RITC (Rhodamine-B) labeled dextran were used for visualzing microvessels and blood flow, respectively. As a model of microemboli, latex microsheres (diameter : around 40 mum), which were labeled with FITC,were injected into a common carotid artery. Based on RITC video-image, we measured internal diameter, length and network structure, of pial microvessels. Based on FITC videoimage, we measured red cell velocity, using a dual window technique. By scanning over an area of the cerebrocortical surface, we reconstructed the network structure of microvessels. The present fkuorescence videoimage showed that i) cerebrocortical microvessels (arterioles and venules) show an acrcading structure with arteriole-arteriole anastomoses ; ii) the arteriolar arcade proivides a multiple pathway for blood flow. Since the arteriolar arcade was like a rotary to connect main streams, blood flow was never stopped when a single arteriole was occluded with microspheres. Under microvascular occlusion due to microemboli, dypath flow-circuits may work to flow blood continuously in the cerebral microvascular network.
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