Silver I A
Ciba Found Symp. 1978 Mar(56):49-67. doi: 10.1002/9780470720370.ch5.
The investigation was designed to identify microenvironmental factors that might be important in the regulation of local blood flow. Cellular microenvironment in terms of Po2, pH, [K+], [Cl-], [Ca2+] and lactate was measured in rat brain by means of specific microelectrodes. Vascular endothelium was stained in vivo with Thioflavine S. Local blood flow was measured with micro hydrogen electrodes. Some intracellular measurements of pH were made in conjunction with extracellular measurements. The main findings were that local autoregulation responses and blood flow changes in response to imposed hypoxic changes were very rapid (1-1.5 s). Microflow responses to changes in local cell activity were limited to a region not more than 250 micron in diameter. Increased blood flow in acute hypoxia occurred within 1-2 s of the fall in tissue Po2 and was much more rapid than changes in either pH or potassium. Intracellular pH changed within 10 s of the onset of severe hypoxia but in all cases the blood flow followed the Po2 much more closely than any other parameter. It is suggested that changes in capillary endothelium and local membrane transmission may play a part in autoregulatory mechanisms.
该研究旨在确定可能在局部血流调节中起重要作用的微环境因素。通过特定的微电极测量大鼠脑中细胞微环境的氧分压（Po2）、pH值、钾离子浓度（[K+]）、氯离子浓度（[Cl-]）、钙离子浓度（[Ca2+]）和乳酸含量。用硫黄素S对体内血管内皮进行染色。用微氢电极测量局部血流。结合细胞外测量进行了一些细胞内pH值测量。主要发现是，局部自动调节反应以及对施加的缺氧变化的血流变化非常迅速（1 - 1.5秒）。对局部细胞活动变化的微血流反应局限于直径不超过250微米的区域。急性缺氧时，血流增加发生在组织Po2下降后的1 - 2秒内，比pH值或钾离子的变化快得多。严重缺氧开始后10秒内细胞内pH值发生变化，但在所有情况下，血流与Po2的变化比与任何其他参数的变化更紧密相关。有人提出，毛细血管内皮的变化和局部膜传递可能在自动调节机制中起作用。
