The influence of protons and zinc ions on the steady-state inactivation of Kv1.3 potassium channels

• Autorzy: Teisseyre A , Mozrzymas J.W.
• Języki publikacji: EN

Abstrakty

EN

Using the whole-cell patch-clamp technique, we investigated the influence of extracellular pH and zinc ions (Zn2+) on the steady-state inactivation of Kv1.3 channels expressed in human lymphocytes. The obtained data showed that lowering the extracellular pH from 7.35 to 6.8 shifted the inactivation midpoint (Vi) by 17.4 ± 1.12 mV (n = 6) towards positive membrane potentials. This shift was statistically significant (p < 0.05). Applying 100 μM Zn2+ at pH 6.8 further shifted the Vi value by 16.55 ± 1.80 mV (n = 6) towards positive membrane potentials. This shift was also statistically significant (p < 0.05). The total shift of the Vi by protons and Zn2+ was 33.95 ± 1.90 mV (n = 6), which was significantly higher (p < 0.05) than the shift caused by Zn2+ alone. The Zn2+-induced shift of the Vi at pH 6.8 was almost identical to the shift at pH = 7.35. Thus, the proton-and Zn2+-induced shifts of the Vi value were additive. The steady-state inactivation curves as a function of membrane voltage were compared with the functions of the steady-state activation. The total shift of the steady-state inactivation was almost identical to the total shift of the steady-state activation (32.01 ± 2.10 mV, n = 10). As a result, the “windows” of membrane potentials in which the channels can be active under physiological conditions were also markedly shifted towards positive membrane potentials. The values of membrane voltage and the normalised chord conductance corresponding to the points of intersection of the curves of steady-state activation and inactivation were also calculated. The possible physiological significance of the observed modulatory effects is discussed herein.

Słowa kluczowe

EN

extracellular pH; zinc ion; patch clamp technique; human lymphocyte; lymphocyte; neuronal excitability; zinc; potassium channel; central nervous system; ion channel

• Wydawca: -
• Czasopismo: Cellular and Molecular Biology Letters
• Rocznik: 2007
• Tom: 12
• Numer: 2
• Opis fizyczny: p.220-230,fig.,ref.

Twórcy

autor

Teisseyre A

• Wroclaw Medical University, Chalubinskiego 10, 50-368 Wroclaw, Poland

autor

Mozrzymas J.W.

Bibliografia

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