Renal Dopamine Not Renal Nerve Mediates Diuretic and Natriuretic Effect of ANF in Rats

腎內多巴胺而非腎神經媒介大鼠對心房利鈉素的利尿和利鈉排泄作用

高美媚(Mei-Mei Kau) ； 黃萬出(Wann-Chu Huang)

《The Chinese Journal of Physiology》 34卷3期 (1991/09) Pp. 317-331

摘要

我們以前的實驗結果顯示單側的急性或慢性腎神經切除並不會阻遏由心房利鈉素所產生的降血壓和增加腎排泄功能的作用。本實驗乃更進一步探究腎神和腎內多巴胺在心房利鈉素對腎臟作用的潛在性角色。實驗是以麻醉大鼠在急性地結紮單側的輸尿管（八隻）、先一天注射蛇根鹼（七隻）、以機械方式控制腎動脈壓（八隻）和阻斷多巴胺第一型受體（八隻）的情況下，測量其對由靜脈或腎動脈內注射心房利鈉素所引起的血壓和腎廓清反應。結果顯示單側結紮輸尿管以引起生理性地降低對側腎臟傳出性交感神經活性時並不能改變由靜脈注射心房利鈉素所產生的利尿和利鈉排泄作用。以蛇根鹼預先處理大鼠則阻遏了心房利鈉素對腎臟的作用；但是，將大鼠的腎動脈壓控制在與蛇根鹼處理者相同的水準時注射心房利鈉素仍可產生利尿和利鈉排泄反應。這些結果近一步支持心房利鈉素的利尿和利鈉排泄作用並非肇因於腎交感傳出性神經活性降低的學說；甚且，心房利鈉素對腎臟的作用乃是經由腎內多巴胺第一型受體被激活有關的機制所致。

並列摘要

Kau,M.M., and W.C.Huang, Renal dopamine not renal nerve mediates diuretic and natriuretic effect of ANF in rats. Chinese J.Physiol.34(3):317-331,1991.Our previous study demonstrated that acutely or chronically unilateral renal denervation did not blunt intravenous ANF-induced hypotensive and ipsilateral renal effects. The present study was further to examine the permissive role of renal nerve and dopamine in the renal action of ANF. Experiments were conducted on anesthetized rats with either acute unilateral ureter ligation (n=8), reserpine pretreatment(10 mg/kg, n=7),mechanically controlled renal arterial pressure(n=8)or blockade of dopamine D1 receptors by SCH23390(n=8,0.8μg/kg.min). The arterial blood pressure and renal clearance responses to intravenous (0.30-0.45 μg/kg.min)or intrarenal(0.10-0.15 μg/kg.min)infusion of ANF were measured. The results showed that unilateral ligation of the ureter to physiologically inhibit the contralateral renal efferent nerve activity did not alter the depressor, diuretic and natriuretic effects of ANF. Reserpine pretreatment blunted the diuretic and natriuretic response to intravenous administration of ANF. However, ANF-induced diuresis and natriuresis was persistently observed in both kidneys of rats with the left renal arterial pressure being controlled at a level comparable to that seen in the reserpine-pretreated group. Blockade of intrarenal dopamine D1 receptors by SCH23390 completely abolished the diuretic and natriuretic response to intrarenal infusion of ANF. These results support the notion that the diuretic and natriuretic effect of ANF is not resulted from a decrease in renal sympathetic efferent nerve activity, and further indicate that a mechanism associated with activation of the renal dopamine D1 receptors mediates the renal effect of ANF in rats.

並列關鍵字

atrial natriuretic factor ； dopamine ； reserpine ； renal nerve ； ureter ligation ； diuresis ； natriuresis ； rat