[Effect of adenosine on isolated afferent arterioles].
We investigated the direct effect of adenosine on afferent arterioles (Af-Arts) and the receptor subtype that mediates the constrictor or dilator action of adenosine. Af-Arts were isolated from the superficial cortex of rabbit kidney and perfused in vitro. Adenosine added to either the lumen or bath constricted the Af-Arts in a dose-dependent manner. This constriction was blocked by the A1 receptor antagonist, 6-oxo-3-(2-phenylpyrazole(1,5-a)pyridin-3-yl)-1 (6H)-pyridazinebutyric acid (FK838) or 8-cyclopentyl-1, 3-dipropylxanthine(DPCPX). We also examined the effect of adenosine on preconstricted Af-Arts with norepinephrine. Adenosine added to either the lumen or bath further constricted the preconstricted Af-Arts. In the presence of FK838, adenosine added to either the lumen or bath dilated the preconstricted Af-Arts, but in a different dose-dependent manner. Adenosine-induced dilation was inhibited by the A2 receptor antagonist, 3, 7-dimetyl-1-propargylxanthine(DMPX). These data indicate that adenosine constricts Af-Arts via A1 receptors and that adenosine dilates preconstricted Af-Arts via A2 receptors when A1 receptors are blocked.
Yaoita
H
H
Second Department of Internal Medicine, Tohoku University School of Medicine, Miyagi, Japan.
Ito
O
O
Arima
S
S
Endo
Y
Y
Takeuchi
K
K
Omata
K
K
Ito
S
S
D000241:Adenosine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007668:Kidney / Q000098:blood supply*; D008297:Male; D058915:Purinergic P1 Receptor Antagonists; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011817:Rabbits; D013805:Theobromine / Q000031:analogs & derivatives / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*; D014970:Xanthines / Q000494:pharmacology
D058915:Purinergic P1 Receptor Antagonists; D011720:Pyrazoles; D011725:Pyridines; D014665:Vasodilator Agents; D014970:Xanthines; C102861:FK 838; C057837:3,7-dimethyl-1-propargylxanthine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000241:Adenosine; D013805:Theobromine