Badzyńska B, Sadowski J, Kompanowska-Jezierska E
Department of Applied Physiology, Medical Research Centre Polish Academy of Sciences, Warsaw.
Arch Int Physiol Biochim. 1990 Aug;98(4):131-40. doi: 10.3109/13813459009113970.
Fluctuations of total electrolyte concentration in the renal medulla were estimated from continuous measurement of tissue electrical admittance (reciprocal impedance) by means of needle electrodes placed in the kidney of anaesthetized rats. To compare effects of two diuretic agents with different sites of action, rats received either furosemide, 0.3 mg/kg i.v. followed by an infusion at 0.3 mg/kg.h, or acetazolamide, a single injection of 10 mg/kg. At this dosage similar increases in renal excretion were obtained with either drug. After furosemide (a loop diuretic) admittance fell sharp within first 10 min, then partly recovered and reached a plateau 35 min after injection. Acetazolamide (inhibitor of proximal reabsorption) caused no changes in admittance compared to the pattern observed in untreated control animals. We conclude that dissipation of tissue electrolytes from the renal medulla is not simply a consequence of diuresis and natriuresis but depends critically on the site of transport inhibition in the nephron.
通过将针电极置于麻醉大鼠的肾脏中，连续测量组织导纳（阻抗的倒数），估算肾髓质中总电解质浓度的波动情况。为比较两种作用部位不同的利尿剂的效果，大鼠分别接受静脉注射0.3mg/kg呋塞米，随后以0.3mg/（kg·h）的速度输注，或单次注射10mg/kg乙酰唑胺。在此剂量下，两种药物均可使肾排泄量出现类似增加。使用呋塞米（一种袢利尿剂）后，导纳在最初10分钟内急剧下降，随后部分恢复，并在注射后35分钟达到平稳状态。与未处理的对照动物所观察到的模式相比，乙酰唑胺（近端重吸收抑制剂）未引起导纳变化。我们得出结论，肾髓质中组织电解质的消散并非仅仅是利尿和利钠的结果，而是严重依赖于肾单位中转运抑制的部位。
