Rasio E A, Bendayan M, Goresky C A
Circ Res. 1977 Dec;41(6):791-8. doi: 10.1161/01.res.41.6.791.
The rete mirabile of the swimbladder of the eeel is a countercurrent exchange organ composed of alternately disposed and venous capillaries. A countercurrent perfusion of these was set up by isolating arterial input and outflow, and venous input and outflow, and perfusing each set of capillaries with oxygenated albumin-containing Krebs-Ringer bicarbonate buffer. Constant arterial infusions containing tracer albumin, inulin, 3-O-methylglucose, urea, and water were begun and tracer concentrations at the outlets of arterial and venous beds were determined. Capillary permeabilities were determined from the resulting steady state values. The method of calculation of permeability values from the data acquired in the rete involves no approximations and appears to yield unequivocal values. For the solutes, the values appear compatible with transcapillary passage by free diffusion. No evidence of increasing restriction (in comparison to the diffuse coefficients) was found over the range of molecular sizes explored. The permeability for labeled water, in relation to the solutes, was too high, and this augmentation was attributed to the larger surface available for its exchange. Despite this larger value, labeled water did not undergo flow-limited exchange. A significant barrier to its distribution is present in this capillary system.
鳗鱼鳔的神奇网是一个逆流交换器官，由交替排列的动脉和静脉毛细血管组成。通过分离动脉输入和输出以及静脉输入和输出，并向每组毛细血管灌注含氧量的含白蛋白的 Krebs-Ringer 碳酸氢盐缓冲液，建立了这些血管的逆流灌注。开始持续动脉输注含示踪白蛋白、菊粉、3-O-甲基葡萄糖、尿素和水，并测定动脉床和静脉床出口处的示踪剂浓度。根据所得稳态值确定毛细血管通透性。从神奇网中获取的数据计算通透性值的方法不涉及近似值，似乎能得出明确的值。对于溶质，这些值似乎与通过自由扩散的跨毛细血管通道相符。在所研究的分子大小范围内，未发现限制增加的证据（与扩散系数相比）。相对于溶质，标记水的通透性过高，这种增加归因于其交换可用的较大表面积。尽管有这个较大的值，标记水并未经历流量限制交换。在这个毛细血管系统中存在对其分布的显著屏障。
