López J M, Roncoroni A, Yeyati N, Villamil M F
Acta Physiol Lat Am. 1975;25(4):347-52.
The aim of this work was to investigate whether the natriuretic effect of furosemide can be wholly explained by the inhibition of a ouabain-sensitive Cl transport in the thick ascending limb of Henle. For this purpose 6 dogs undergoing moderate saline diuresis received 100 mug ouabain/kg into the left renal artery followed by 2 mg furosemide/kg IV. Urine was collected from both kidneys and blood samples taken at regular intervals. Ouabain produced a unilateral increase in Na excretion and little change in CCR and water and K excretion. IV furosemide increased Na, K and water excretion in both kidneys. Since Na excretion in the left kidney was already exhanced by ouabain the increment was lesser than in the right kidney. As a result water and electrolyte excretion became similar in both kidneys. Although ouabain did not prevent the renal response to furosemide, the effects of both drugs were not additive. This suggests that in addition to the thick ascending limb, furosemide acts in some other tubular segment which is insensitive to ouabain. Since furosemide is known to also inhibit passive Cl movements, a second site of action could be in the thin ascending limb of Henle, which lacks any active transport mechanism but is highly permeable to Cl.
这项工作的目的是研究速尿的利钠作用是否能完全由抑制亨氏袢升支粗段中哇巴因敏感的氯转运来解释。为此，6只处于中度盐水利尿状态的狗经左肾动脉注射100微克/千克哇巴因，随后静脉注射2毫克/千克速尿。从双侧肾脏收集尿液，并定期采集血样。哇巴因使钠排泄单侧增加，而内生肌酐清除率、水和钾排泄变化不大。静脉注射速尿增加了双侧肾脏的钠、钾和水排泄。由于哇巴因已使左肾钠排泄增加，所以其增量小于右肾。结果双侧肾脏的水和电解质排泄变得相似。虽然哇巴因并未阻止肾脏对速尿的反应，但两种药物的作用并非相加。这表明除了升支粗段外，速尿还作用于其他对哇巴因不敏感的肾小管节段。由于已知速尿还能抑制氯的被动转运，所以第二个作用部位可能在亨氏袢升支细段，该段缺乏任何主动转运机制，但对氯高度通透。
