Bryan R M, Duckrow R B
Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA.
Am J Physiol. 1995 Aug;269(2 Pt 2):H583-9. doi: 10.1152/ajpheart.1995.269.2.H583.
Radial columns in the cerebral cortex, sometimes seen in autoradiographic methods for measuring cerebral blood flow, were studied. Radioactively labeled tracers were injected into the internal carotid artery in pentobarbital sodium-anesthetized rats. The cortical patterns of tracer uptake were determined using autoradiography. When tracers for measuring cerebral blood flow were administered, cortical columns were apparent in the autoradiograph. The darker columns (higher tracer concentration) in the image aligned with penetrating arterioles, suggesting that the tracer was being removed from the penetrating arterioles. In another experiment, [14C]glucose was used as a qualitative blood flow tracer. Modeling of glucose uptake predicts that 26-29% more glucose should be extracted in the dark columns than the light columns if the columns represent capillary blood flow. [14C]glucose did not produce the cortical columns consistent with the model prediction. We conclude that capillary blood flow in the cortex is not organized in radial columns of higher and lower flow. The results support the idea that the flow tracers are removed from blood primarily in the penetrating arterioles.
对大脑皮质中的放射状柱进行了研究，这些放射状柱有时在用于测量脑血流量的放射自显影方法中可见。将放射性标记的示踪剂注入戊巴比妥钠麻醉的大鼠的颈内动脉。使用放射自显影法确定示踪剂摄取的皮质模式。当给予测量脑血流量的示踪剂时，放射自显影片中可见皮质柱。图像中较暗的柱（较高的示踪剂浓度）与穿透性小动脉对齐，表明示踪剂正从穿透性小动脉中被清除。在另一项实验中，[14C]葡萄糖被用作定性血流示踪剂。葡萄糖摄取模型预测，如果这些柱代表毛细血管血流，那么较暗的柱中提取的葡萄糖应比较亮的柱多26 - 29%。[14C]葡萄糖并未产生与模型预测一致的皮质柱。我们得出结论，皮质中的毛细血管血流并非以较高和较低血流的放射状柱形式组织。这些结果支持了这样一种观点，即血流示踪剂主要在穿透性小动脉中从血液中被清除。
