Filho E M, Malnic G
Pflugers Arch. 1976 Jun 22;363(3):211-7. doi: 10.1007/BF00594603.
The pH of peritubular capillaries was measured by means of antimony microelectrodes, during their perfusion with mammalian Ringer's solutions at different pH, in control and acetazolamide infused rats. In capillaries perfused with a solution more acid than blood, significant alkalinization was observed at increasing distances from the point of perfusion, while during perfusions with more alkaline solutions, acidification was observed. Plotting the pH change observed per micrometer of distance from the perfusion point against the pH of the perfusing solution, the pH in equilibrium with tubular cells was interpolated. A value of 7.51 +/- 0.01 was found for control rats, significantly higher than the mean arterial blood pH of this group, of 7.39. In acetazolamide infused rats an equilibrium pH of 7.44 +/- 0.02 was found, still higher than the blood pH of 7.34. The slope of these lines was significantly greater in control than in acetazolamide treated rats. This slope was shown to evaluate permeability to the ions responsible for acid-base balance. The present data suggest that peritubular alkalinization is reduced after carbonic anhydrase inhibition due to decreased peritubular permeability to the involved ions, which represents a further site of action of these inhibitors.
在对照大鼠和注入乙酰唑胺的大鼠中，使用锑微电极在以不同pH值的哺乳动物林格氏液灌注时，测量了肾小管周围毛细血管的pH值。在用比血液酸性更强的溶液灌注的毛细血管中，在距灌注点距离增加时观察到显著的碱化现象，而在用碱性更强的溶液灌注时，则观察到酸化现象。将每微米距离灌注点处观察到的pH变化与灌注溶液的pH值作图，可推算出与肾小管细胞平衡时的pH值。对照大鼠的该值为7.51±0.01，显著高于该组的平均动脉血pH值7.39。在注入乙酰唑胺的大鼠中，平衡pH值为7.44±0.02，仍高于血液pH值7.34。这些线的斜率在对照大鼠中显著大于在乙酰唑胺处理的大鼠中。该斜率被证明可评估对负责酸碱平衡的离子的通透性。目前的数据表明，碳酸酐酶抑制后肾小管周围碱化减少，这是由于肾小管对相关离子的通透性降低，这代表了这些抑制剂的另一个作用位点。
