Share This Author
The Na channel voltage sensor associated with inactivation is localized to the external charged residues of domain IV, S4.
Extracellular divalent and trivalent cation effects on sodium current kinetics in single canine cardiac Purkinje cells.
1. The effects of the extracellular divalent cations barium, calcium, cadmium, cobalt, magnesium, manganese, nickel and zinc and the trivalent cation lanthanum on macroscopic sodium current (INa)…
Mechanisms of extracellular divalent and trivalent cation block of the sodium current in canine cardiac Purkinje cells.
Fits of single‐site binding curves to peak INa in response to step depolarizations at positive test potentials varied as a function of [Ni2+], consistent with the hypothesis that Ni2+ blocked with similar affinity at a Voltage‐dependent and a voltage‐independent site.
Open sodium channel properties of single canine cardiac Purkinje cells.
Sodium current in voltage clamped internally perfused canine cardiac Purkinje cells.
Time-dependent changes in kinetics of Na+ current in single canine cardiac Purkinje cells.
It is concluded that the channel-voltage sensor responds to a changing fraction of the applied voltage during an experiment, producing similar rates of shift of voltage-dependent availability, conductance, and deactivation time constants.
Molecular Action of Lidocaine on the Voltage Sensors of Sodium Channels
Lidocaine's most dramatic effect was to alter the voltage-dependent charge movement of the S4 in domain IV such that it accounted for the appearance of additional gating charge at potentials near −100 mV, suggesting that lidOCaine's actions on Na channel gatingcharge result from allosteric coupling of the binding site(s) of lidocaine to the voltage sensors formed by the S 4 segments in domains III and IV.
Sodium channel molecular conformations and antiarrhythmic drug affinity.
Voltage-dependent open-state inactivation of cardiac sodium channels: gating current studies with Anthopleurin-A toxin
Comparison of Ig recorded in response to step depolarizations before and after modification by Ap-A toxin showed that toxin-modified gating currents decayed faster and had decreased initial amplitudes, matching data previously reported from single Na channel studies in heart at the same temperature.
Modification of inactivation in cardiac sodium channels: ionic current studies with Anthopleurin-A toxin
It is concluded that Ap-A selectively modifies Na channel in activation from the open state with little effect on channel activation or on inactivation from closed state(s).