Voltage‐dependent inactivation of inward‐rectifying single‐channel currents in the guinea‐pig heart cell membrane.
Key result
Inward-rectifying K+ channels in guinea-pig ventricular cells are partially inactivated by hyperpolarization, with open state probability decreasing from approximately 0.15 at -50 mV to 0.02 at -110 mV.
Population
Isolated ventricular heart cells of the guinea-pig
Design
Preclinical
Authors
Discussion
Loading...
Member takes
Implication
May underlie time-dependent IK1 decay in ventricular myocytes; leaves open relevance to human electrophysiology.
Key Points
- This research aims to investigate how inward-rectifying K+ channels behave under varying voltage conditions.
- Isolated guinea-pig ventricular heart cells were analyzed using the patch-clamp technique.
- The voltage-dependent properties of K+ channels were examined from 0 mV to -120 mV.
- Various models were employed to interpret the kinetics of channel states and lifetimes.
- Inward-rectifying current showed stronger inactivation with increased hyperpolarization, with p values of 0.15 at -50 mV and 0.02 at -110 mV.
- The current-voltage relation exhibited a negative slope for potentials more negative than -50 mV.
- Channel openings were disrupted by Cs+ and Ba2+, leading to altered opening durations and frequencies.
Structured PICO
P
Population
Isolated ventricular heart cells of the guinea-pig
I
Intervention
Voltage pulses (0 to -120 mV) with 145 mM-KCl on the extracellular side; application of Cs+ (0.1 mM) or Ba2+ (0.5 mM)
O
Outcome
Voltage-dependent gating properties (inactivation, lifetimes of open and closed states, probability of open state)surrogate
Inward-rectifying K+ channels in guinea-pig ventricular cells undergo voltage-dependent inactivation by hyperpolarization, which may account for time-dependent decreases in whole-cell currents.
Cite This Study
Sakmann et al. (1984) studied Inward-rectifying K+ currents. Voltage pulses and channel blockers (Cs+, Ba2+) was evaluated on Voltage-dependent gating properties and inactivation of inward-rectifying K+ channels. Inward-rectifying K+ channels in guinea-pig ventricular cells are partially inactivated by hyperpolarization, with open state probability decreasing from approximately 0.15 at -50 mV to 0.02 at -110 mV.