All nucleoside transporters in bovine chromaffin cells are nitrobenzylthioinosine sensitive.
Nitrobenzylthioinosine is an effective inhibitor of adenosine transport in chromaffin cells. When adenosine transport was measured at a 0.15 microM adenosine concentration, in the presence of variable concentrations of nitrobenzylthioinosine, ranging from 10(-14) to 10(-6) M, a half-maximal inhibitory concentration value (IC50) of 1 +/- 0.3 nM was deduced. This compound has the capacity to inhibit the total adenosine transport at 10(-7) M concentration. Nitrobenzylthioinosine acts in a non-competitive manner in blocking adenosine transport, as deduced from a Dixon plot, with a constant inhibition value (K1) of 0.01 +/- 0.003 nM. The results suggest that all nucleoside transporters present in bovine chromaffin cells are sensitive to the nitrobenzylthioinosine inhibition.
Torres
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Departamento Bioquímica, Facultad de Veterinaria, Universidad Complutense de Madrid, Spain.
Fideu
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MD
Miras-Portugal
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MT
D000241:Adenosine / Q000493:pharmacokinetics*; D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004176:Dipyridamole / Q000378:metabolism; D007288:Inosine / Q000031:analogs & derivatives*; D013868:Thioinosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
D002352:Carrier Proteins; D013868:Thioinosine; D007288:Inosine; D004176:Dipyridamole; C001789:4-nitrobenzylthioinosine; D000241:Adenosine