麻醉大鼠急性容量扩张期间的肾神经与α2-肾上腺素能作用

Renal nerve and alpha 2-adrenergic action during acute volume expansion in the anaesthetized rat.

Young P J, Miller J H

School of Biological Sciences, Victoria University of Wellington, New Zealand.

Clin Exp Pharmacol Physiol. 1999 Aug;26(8):608-13. doi: 10.1046/j.1440-1681.1999.03094.x.

Abstract

The effects of renal denervation and alpha 2-adrenoceptor blockade on diuresis and natriuresis in response to acute volume expansion (VE) were investigated in anaesthetized rats. 2. In normal rats, a 30 min intravascular VE of up to 7.5% of bodyweight caused a significant diuresis and natriuresis. 3. Denervation enhanced the diuretic effect of VE by 39%, while alpha 2 blockade by 12 mumol/kg per h rauwolscine significantly inhibited the response by 61% in innervated kidneys and 43% in denervated kidneys. 4. Similar results were found for natriuresis in both innervated and denervated kidneys. 5. The results demonstrate that renal sympathetic nerve activity inhibits part of the increase in sodium and water excretion caused by VE, since denervation increased excretion under these conditions. The contribution of renal nerves to the control of renal function, however, decreases during the response to VE. 6. alpha 2-Adrenoceptor action enhanced the diuretic and natriuretic effects of VE by mechanisms otherwise unrelated to renal nerve activity.

摘要

在麻醉大鼠中研究了肾去神经支配和α₂肾上腺素能受体阻断对急性容量扩张（VE）引起的利尿和利钠作用的影响。2. 在正常大鼠中，高达体重7.5%的30分钟血管内VE引起显著的利尿和利钠作用。3. 去神经支配使VE的利尿作用增强了39%，而每小时12 μmol/kg的萝芙木碱α₂受体阻断在神经支配的肾脏中显著抑制反应61%，在去神经支配的肾脏中抑制43%。4. 在神经支配和去神经支配的肾脏中利钠作用也得到了类似结果。5. 结果表明，肾交感神经活动抑制了VE引起的部分钠和水排泄增加，因为在这些条件下去神经支配增加了排泄。然而，在对VE的反应过程中，肾神经对肾功能控制的贡献降低。6. α₂肾上腺素能受体作用通过与肾神经活动无关的机制增强了VE的利尿和利钠作用。