1. Ionic dependence of adenosine uptake into cultured astrocytes.
- Author
-
Bender AS, Woodbury DM, and White HS
- Subjects
- Animals, Animals, Newborn, Astrocytes drug effects, Benzopyrans pharmacology, Biological Transport, Calcimycin pharmacology, Calcium pharmacology, Carbonyl Cyanide m-Chlorophenyl Hydrazone pharmacology, Cells, Cultured, Cromakalim, Furosemide pharmacology, Glyburide pharmacology, Kinetics, Mice, Niacinamide analogs & derivatives, Niacinamide pharmacology, Nicorandil, Nigericin pharmacology, Omeprazole pharmacology, Pyrroles pharmacology, Valinomycin pharmacology, Vasodilator Agents pharmacology, Adenosine metabolism, Astrocytes metabolism, Cerebral Cortex metabolism, Ionophores pharmacology, Potassium pharmacology, Sodium pharmacology
- Abstract
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.
- Published
- 1994
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