Aki Y, Shoji T, Hasui K, Fukui K, Tamaki T, Iwao H, Abe Y
Department of Pharmacology, Kagawa Medical School, Japan.
Jpn J Pharmacol. 1990 Dec;54(4):433-40. doi: 10.1254/jjp.54.433.
Our purpose was to localize the intrarenal vascular sites of action of adenosine and glucagon. Renal blood flow (RBF) and glomerular filtration rate (GFR) were measured in anesthetized dogs, and renal perfusion pressure (RPP) was varied by an adjustable aortic clamp. At normal RPP, RBF was increased by all agents. In contrast, GFR was increased by glucagon, decreased by adenosine and unchanged by acetylcholine (ACh) or adenosine plus glucagon. The increases in RBF by glucagon occurred only at RPPs within the autoregulatory pressure range, and renal autoregulatory capability was attenuated during the infusion of glucagon. In contrast, adenosine increased RBF at RPPs both within and below the autoregulatory pressure range, and the autoregulatory capability was not perceptibly impaired. Superimposition of glucagon to adenosine caused further vasodilation, and the autoregulatory efficiency was completely attenuated. There was no difference between the RPP-RBF or RPP-GFR relations obtained during infusion of adenosine plus glucagon and ACh, which dilates both the afferent and efferent arterioles. It is generally accepted that afferent arteriolar resistance attains a minimum value at RPP near the lower limit of the autoregulatory range. Thus, our data indicate that glucagon and adenosine preferentially dilate the afferent arteriole and the efferent arteriole, respectively.
我们的目的是确定腺苷和胰高血糖素在肾内的血管作用部位。在麻醉犬身上测量肾血流量（RBF）和肾小球滤过率（GFR），并通过可调节的主动脉夹改变肾灌注压（RPP）。在正常RPP时，所有药物均可增加RBF。相比之下，胰高血糖素可增加GFR，腺苷可降低GFR，乙酰胆碱（ACh）或腺苷加胰高血糖素对GFR无影响。胰高血糖素引起的RBF增加仅发生在自动调节压力范围内的RPP时，且在输注胰高血糖素期间肾自动调节能力减弱。相比之下，腺苷在自动调节压力范围之内和以下的RPP时均可增加RBF，且自动调节能力无明显受损。在腺苷加胰高血糖素输注期间获得的RPP-RBF或RPP-GFR关系与ACh（可使入球小动脉和出球小动脉均扩张）输注期间获得的关系无差异。一般认为，在接近自动调节范围下限的RPP时，入球小动脉阻力达到最小值。因此，我们的数据表明，胰高血糖素和腺苷分别优先扩张入球小动脉和出球小动脉。
