Adenosine receptors in basolateral membranes of rat renal cortex.
High affinity binding sites for adenosine were identified in rat kidney cortex basolateral membranes. Kinetic analysis indicates two sets of [3H]adenosine, [3H]ADO, binding sites, one with high affinity and Kd = 0.84 +/- 0.25 microM, one with low affinity and Kd = 4.74 +/- 0.37 microM. The ADO receptors were further characterized using ADO analogs as binding inhibitors. The most potent inhibitor of [3H]ADO binding was N-methyl-adenosine with a Kd of 5 microM, whereas 2-deoxyadenosine was about 50 times less potent. The binding of [3H]phenylisopropyladenosine, [3H]PIA, and [3H]-N-ethylcarboxamidoadenosine, [3H]NECA, to basolateral membranes was rapid and reversible. The Scatchard plot of [3H]PIA binding showed monophasic curves for experiments performed at 0 degrees C and 37 degrees C. The apparent Kd of [3H]PIA binding at 0 degrees C was 0.19 +/- 0.05 nM and 0.34 +/- 0.07 nM at 37 degrees C. The binding of [3H]NECA to basolateral membranes was found with an apparent affinity Kd of 110 +/- 50 nM at 0 degrees C. Pretreatment of membranes with N-ethylmaleimide (NEM) inhibited the [3H]PIA binding and did not affect the [3H]NECA binding. These results demonstrate that both A1 and A2 adenosine receptors are present in basolatertal membranes of rat kidney.
Jakubowski
Z
Z
Department of Clinical Biochemistry, Medical Academy, Gdańsk, Poland.
Skowroński
R
R
Matecki
A
A
Mohuczy
D
D
Pawełczyk
T
T
Stepiński
J
J
Angielski
S
S
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D000243:Adenosine Deaminase / Q000378:metabolism; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D001667:Binding, Competitive; D002855:Chromatography, Thin Layer; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D010660:Phenylisopropyladenosine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011983:Receptors, Purinergic / Q000378:metabolism*; D013696:Temperature
D011983:Receptors, Purinergic; D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); D000243:Adenosine Deaminase; D000241:Adenosine