Katsuyuki Miura (1), Michiaki Okumura (2), Shinya Yamanaka (1), Shokei
Kim (1) and Hiroshi Iwao (1)
(1) Department of Pharmacology, Osaka City University Medical School, 1-4-3 Asahimachi, Abeno, Osaka 545-8585, Japan
(2) Department of Internal Medicine, Osaka City General Hospital, 2-13-22, Mlyakojima-Hondori, Miyakojima, Osaka 534-0021, Japan
Abstract: Direct effects of adenosine A2 receptor activation on renal function were examined in dogs. When renal perfusion pressure was maintained constant at 100 mmHg, renal administration of a selective A2 receptor agonist, CGS 21680C (sodium salt of CGS 21680, 2-[p-(2-carboxyethyl) phenethylamino]-5'-N-ethylcarboxamido adenosine) 1 microgEkg-1Emin-1), although it decreased blood pressure by 20 mmHg, increased renal blood flow and renin release, whereas glomerular filtration rate and urine flow were unaffected, These results suggest that stimulation of renal A2 receptor led to both afferent and efferent arteriolar dilatation, whereas renal A2 receptor plays a minor role in urine formation. CGS 21680C induced renin release and tachycardia that were blocked by propranolol, indicating these effects of A2 receptor stimulation appeared to be indirect.
Keywords: Adenosine, Adenosine A2 receptor, Renal hemodynamics