Cserr H F, Cooper D N, Suri P K, Patlak C S
Am J Physiol. 1981 Apr;240(4):F319-28. doi: 10.1152/ajprenal.1981.240.4.F319.
Experiments were carried out to evaluate the role of convection in the removal of large molecules from brain interstitial fluid. Radiolabeled test compounds were injected into the caudate nucleus of anesthetized rats through a guide cannula implanted 1 wk previously and the concentrations of isotope in brain and cerebrospinal fluid (CSF) determined at various times after injection. Control studies with 22Na indicate that the permeability of the blood-brain barrier is normal in tissue surrounding the intracerebral injection cannula. For 69,000 dalton serum albumin, 4,000 dalton polyethylene glycol, and 900 dalton polyethylene glycol, clearance from brain approximates a single exponential decay with half times of disappearance of 12.2, 12.6, and 14.4 h, respectively. Similarly in efflux rate, despite a fivefold difference in diffusion coefficient, is consistent with convective losses from brain, and the maximal rate of interstitial fluid removal estimated on the basis of these data is 0.11 microliter.g brain-1.min-1. Only 10-20% of total efflux is into bulk CSF withdrawn from the cisterna magna.
开展实验以评估对流在从脑间质液中清除大分子方面的作用。通过1周前植入的引导套管将放射性标记的测试化合物注入麻醉大鼠的尾状核，并在注射后的不同时间测定脑和脑脊液（CSF）中的同位素浓度。用22Na进行的对照研究表明，脑内注射套管周围组织中的血脑屏障通透性正常。对于69,000道尔顿的血清白蛋白、4,000道尔顿的聚乙二醇和900道尔顿的聚乙二醇，从脑中清除的过程近似于单指数衰减，消失半衰期分别为12.2、12.6和14.4小时。同样在流出速率方面，尽管扩散系数相差五倍，但与从脑中的对流损失一致，根据这些数据估计的间质液最大清除速率为0.11微升·克脑-1·分钟-1。总流出量中只有10 - 20%进入从大池抽出的大量脑脊液中。
