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001-es BibID:	BIBFORM005515
Első szerző:	Somodi Sándor (belgyógyász)
Cím:	Effects of changes in extracellular pH and potassium concentration on Kv1.3 inactivation / Somodi S., Hajdu P., Gáspár R., Panyi G., Varga Z.
Dátum:	2008
Megjegyzések:	The Kv1.3 channel inactivates via the P/C-type mechanism, which is influenced by a histidine residue in the pore region (H399, equivalent of Shaker 449). Previously we showed that the electric field of the protonated histidines at low extracellular pH (pH(e)) creates a potential barrier for K(+) ions just outside the pore that hinders their exit from the binding site controlling inactivation (control site) thereby slowing inactivation kinetics. Here we examined the effects of extracellular potassium [K(+)](e) and pH(e) on the rate of inactivation of Kv1.3 using whole-cell patch-clamp. We found that in 150 mM [K(+)](e )inactivation was accelerated upon switching to pH(e) 5.5 as opposed to the slowing at 5 mM [K(+)](e). The transition from slowing to acceleration occurred at 40 mM [K(+)](e), whereas this "turning point" was at 20 mM [K(+)](e) for inward currents. The rate of entry of Ba(2+) ions from the extracellular space to the control site was significantly slowed by low pH(e) in wild-type hKv1.3, but it was insensitive to pH(e) in H399K and H399L mutants. Based on these observations we expanded our model and propose that the potential barrier created by the protonated histidines impedes the passage of K(+) ions between the extracellular medium and the control site in both directions and the effect on inactivation rate (acceleration or slowing) depends on the relative contribution of filling from the extracellular and intracellular sides.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	European Biophysics Journal. - 37 : 7 (2008), p. 1145-1156. -
További szerzők:	Hajdu Péter (1975-) (biofizikus) Gáspár Rezső (1944-) (biofizikus) Panyi György (1966-) (biofizikus) Varga Zoltán (1969-) (biofizikus, szakfordító)
Internet cím:	elektronikus változat DOI
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