Ionic dependence of adenosine uptake into cultured astrocytes.
Adenosine uptake in cultured astrocytes is dependent on various ions and energy metabolism. The Na(+)-gradient plays an important role, since nigericin, ouabain, amiloride and substitution of Na+ with choline inhibited adenosine uptake. The proton-gradient was of importance, since carbonylcyanide m-chlorophenylhydrozone (CCCP) and omeprazole also inhibited adenosine uptake. Furthermore, adenosine uptake was dependent on Cl- anion. Substitution of Cl- with isethionate, as well as DIDS or furosemide inhibited adenosine uptake. Adenosine uptake was also sensitive to Ca2+ gradient, removal of extracellular Ca2+ and calcimycin inhibited adenosine uptake. Adenosine uptake was not dependent on extracellular K+ and was not affected by valinomycin. Although, K(+)-channel openers (BRL 34195 and nicorandil) as well as the K(+)-channel antagonist, glyburide, inhibited adenosine uptake, the inhibitory effect of BRL 34915 was not antagonized by glyburide. Rotenone and 2,4-dinitrophenol also inhibited adenosine uptake. Ionic dependence and metabolic energy dependence of adenosine uptake suggest that uptake is primarily an active process.
Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City 84112.
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Bender
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Woodbury
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White
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001578:Benzopyrans / Q000494:pharmacology; D001692:Biological Transport; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D019806:Cromakalim; D005665:Furosemide / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D009536:Niacinamide / Q000031:analogs & derivatives / Q000494:pharmacology; D020108:Nicorandil; D009550:Nigericin / Q000494:pharmacology; D009853:Omeprazole / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology*; D014634:Valinomycin / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D001578:Benzopyrans; D007476:Ionophores; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; D014634:Valinomycin; D009536:Niacinamide; D020108:Nicorandil; D000001:Calcimycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D005665:Furosemide; D012964:Sodium; D000241:Adenosine; D009853:Omeprazole; D009550:Nigericin; D011188:Potassium; D005905:Glyburide; D002118:Calcium