AMINOPHYLLINE INHIBITS RENAL VASOCONSTRICTION PRODUCED BY INTRARENAL HYPERTONIC SALINE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 225  (3) , 611-615
Abstract
An intrarenal infusion saline to Na-depleted dogs causes an acute reduction in renal blood flow (RBF) which was postulated to be due to tubuloglomerular feedback (TGF). Adenosine may be 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 were investigated in Na-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 < 0.05) reduced RBF both before (-27 .+-. 4%) and during (-16 .+-. 9%) an infusion with aminophylline vehicle. In a 2nd group of animals (n = 5), an intrarenal hypertonic saline infusion reduced RBF before (-33 .+-. 8%; P < 0.05), but not during an intrarenal aminophylline infusion (2.5 mg/min). Aminophylline evidently inhibits the renal vascular response to hypertonic saline, and the renal response to hypertonic saline might be mediated by intrarenal adenosine release.

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