Gerkens J F, Heidemann H T, Jackson E K, Branch R A
J Pharmacol Exp Ther. 1983 Jun;225(3):611-5.
An intrarenal infusion of hypertonic saline to sodium-depleted dogs causes an acute reduction in renal blood flow (RBF) which has been postulated to be due to tubuloglomerular feedback (TGF). Adenosine has been suggested as a mediator of TGF, as adenosine receptor blockade with methylxanthines inhibits TGF. In order to test further the hypothesis that the renal response to hypertonic saline is mediated by TGF, the RBF response to intrarenal hypertonic saline infusions have been investigated in sodium-depleted dogs before and after either an infusion of vehicle or an intrarenal infusion of aminophylline. Aminophylline (2.5 mg/min), at a dose which did not change basal RBF or responses to bolus doses of angiotensin II, inhibited the responses to intrarenal bolus doses of adenosine. In control dogs (n = 5), a 10-min intrarenal infusion of hypertonic saline significantly (P less than .05) reduced RBF both before (-27 +/- 4%) and during (-16 +/- 9%) an infusion with aminophylline vehicle. In a second group of animals (n = 5), an intrarenal hypertonic saline infusion reduced RBF before (-33 +/- 8%; P less than .05), but not during an intrarenal aminophylline infusion (2.5 mg/min). We conclude that aminophylline inhibits the renal vascular response to hypertonic saline and that the renal response to hypertonic saline might be mediated by intrarenal adenosine release.
给缺钠犬肾内输注高渗盐水会导致肾血流量（RBF）急性减少，据推测这是由于肾小管-肾小球反馈（TGF）所致。腺苷被认为是TGF的介质，因为用甲基黄嘌呤阻断腺苷受体会抑制TGF。为了进一步检验高渗盐水的肾反应由TGF介导这一假说，我们研究了在缺钠犬肾内输注高渗盐水前后，分别输注溶媒或肾内输注氨茶碱时的肾血流量反应。氨茶碱（2.5毫克/分钟），该剂量不会改变基础肾血流量或对大剂量血管紧张素II的反应，可抑制对肾内大剂量腺苷的反应。在对照犬（n = 5）中，肾内输注10分钟高渗盐水在输注氨茶碱溶媒之前（-27±4%）和期间（-16±9%）均显著（P<0.05）降低了肾血流量。在第二组动物（n = 5）中，肾内输注高渗盐水在肾内输注氨茶碱（2.5毫克/分钟）之前降低了肾血流量（-33±8%；P<0.05），但在输注期间未降低。我们得出结论，氨茶碱抑制肾血管对高渗盐水的反应，且肾对高渗盐水的反应可能由肾内腺苷释放介导。
