Modulation of human ether-a-go-go-related K+ (HERG) channel inactivation by Cs+ and K+
Key result
Raising external Cs+ concentration to 135 mM dramatically slowed HERG channel inactivation and shifted the steady-state inactivation curve by 25 mV in the depolarized direction (P<0.01).
Population
Human ether-a-go-go-related K+ (HERG) channels
Comparison
Raising the concentration of external Cs+ or K+o vs Lower concentrations of external K+ or Cs+
Design
Preclinical
Authors
Discussion
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Implication
External Cs+ effects on HERG should not change practice; leaves open physiological K+ modulation of inactivation in native myocytes.
Structured PICO
P
Population
Human ether-a-go-go-related K+ (HERG) channels
I
Intervention
Raising the concentration of external Cs+ (Cs+o) or K+o
C
Comparator
Lower concentrations of external K+ or Cs+ (e.g., 5 mM K+o)
O
Outcome
HERG channel inactivation (time constants and steady-state inactivation curve)surrogate
Main Result
p-value: p=<0.01
External Cs+ and K+ significantly slow HERG channel inactivation, highlighting the importance of ion-channel interactions during the onset of inactivation.
Cite This Study
Zhang et al. (2003) studied this question. External Cs+ (Cs+o) vs. 5 mM K+o was evaluated on HERG channel inactivation time constants and steady-state inactivation curve (p=<0.01). Raising external Cs+ concentration to 135 mM dramatically slowed HERG channel inactivation and shifted the steady-state inactivation curve by 25 mV in the depolarized direction (P<0.01).