Properties of the Ca2+ influx reveal the duality of events underlying the activation by vanadate and fluoride of the Gárdos effect in human red blood cells

FEBS Letters

Peterajová, Elena²  Varečka, Ĺudovı́t¹  Pı́šová, Erika² 

[1] Department of Biochemistry and Microbiology, Slovak University of Technology, Radlinského 9, 81237 Bratislava, Slovakia;Pinel Psychiatric Hospital, 90218 Pezinok, Slovakia

关键词: Red blood cell;    NaVO3;    NaF;    Ca2+ influx;    Gárdos effect;   

DOI  :  10.1016/S0014-5793(98)00902-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The properties of the ⁴⁵Ca²⁺ influx by human red blood cells (RBC) induced by NaVO₃ or NaF were compared. The NaVO₃-induced ⁴⁵Ca²⁺ influx was slower and less extensive than that induced by NaF. Both processes were saturable with Ca²⁺. Substitution of Na⁺ by K⁺ inhibited the ⁴⁵Ca²⁺ influx induced by NaVO₃ but stimulated that by NaF. The NaVO₃-induced Ca²⁺ influx was sensitive to nifedipine (IC₅₀=50 mol/l), Cu²⁺ (IC₅₀=9 mol/l), DTNB (5,5′-dithiobis-(dinitrobenzoic acid)) (IC₅₀=12 mol/l) (maximal inhibition 16%, 18%, and 28%, respectively, if NaF was used as inducer). On the other hand, tetrodotoxin (TTX) and cyclosporin A inhibited only the NaF-induced ⁴⁵Ca²⁺ influx (IC₅₀=21 mol/l and 28 mol/l, respectively). Pig RBC, known not to display the NaVO₃-induced Ca²⁺ influx, exhibited Ca²⁺ influx induced by NaF. The results show that NaVO₃ activates the Ca²⁺ influx via a pathway homologous to the L-type Ca²⁺ channel while the NaF-induced Ca²⁺ influx is mediated via the TTX-sensitive Na⁺ channel in the presence of NaF with possible participation of calcineurin or cyclophilin. Thus, the Gárdos effect induced by NaVO₃ and NaF represents two phenomena activated by different mechanisms present in the cryptic state in the RBC membrane.

【 授权许可】

Unknown