Velázquez H, Wright F S
Am J Physiol. 1986 Jun;250(6 Pt 2):F1013-23. doi: 10.1152/ajprenal.1986.250.6.F1013.
Diuretic drugs were used to characterize mechanisms involved in transporting sodium, chloride, and potassium across the wall of surface distal tubules of the rat kidney using in vivo microperfusion techniques. Both furosemide and chlorothiazide inhibited sodium and chloride absorption but did not affect the rate of potassium secretion or the transepithelial voltage. However, chlorothiazide inhibited sodium and chloride absorption more completely than furosemide and was additive to the effect of furosemide; furosemide was ineffective if chlorothiazide was already present. In contrast to the effect of furosemide, bumetanide did not affect sodium and chloride absorption but did increase potassium secretion. Amiloride reduced sodium absorption and potassium secretion without affecting net chloride absorption. These effects were additive to those of chlorothiazide. In the loop of Henle bumetanide was more effective than furosemide in inhibiting net sodium potassium and chloride absorption. It appears that cells of the distal tubule in the rat possess an Na-Cl cotransport mechanism that differs from the Na-K-2Cl cotransport mechanism found in the thick ascending limb. Sodium transport also proceeds via a conductive pathway that is inhibited by amiloride. The two modes of sodium transport, conductive and coupled to chloride, may occur in different cell types along the distal tubule.
利用体内微灌注技术，使用利尿药物来表征参与大鼠肾脏表面远曲小管壁钠、氯和钾转运的机制。呋塞米和氯噻嗪均抑制钠和氯的重吸收，但不影响钾分泌速率或跨上皮电压。然而，氯噻嗪比呋塞米更完全地抑制钠和氯的重吸收，且与呋塞米的作用相加；如果已经存在氯噻嗪，呋塞米则无效。与呋塞米的作用相反，布美他尼不影响钠和氯的重吸收，但确实增加了钾分泌。氨氯地平减少钠重吸收和钾分泌，而不影响氯的净重吸收。这些作用与氯噻嗪的作用相加。在髓袢升支粗段，布美他尼在抑制钠、钾和氯的净重吸收方面比呋塞米更有效。大鼠远曲小管细胞似乎具有一种钠 - 氯共转运机制，该机制不同于在髓袢升支粗段发现的钠 - 钾 - 2氯共转运机制。钠转运也通过氨氯地平抑制的传导途径进行。钠转运的两种模式，即传导性和与氯偶联的模式，可能在远曲小管的不同细胞类型中发生。
