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.
Bender
A S
AS
Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City 84112.
Woodbury
D M
DM
White
H S
HS
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