Subconductance states in cardiac sodium channels.
Single Na channel currents were studied in cell-attached patches from guinea-pig ventricular myocytes in the presence of DPI 201-106. In addition to openings with a single channel conductance of 15 pS, two other types of events occur that are characterized by a conductance of 5 and 8 pS. The low conductance state is less sensitive to block by TTX than the higher conductance states. The medium conductance state has a reversal potential which is similar to the high conductance channel. It is argued that the low conductance channel is a second type of Na channel, whereas the medium conductance channel appears to be a low conductance substate of the normal Na channels.
Nilius
B
B
Julius Bernstein Institute of Physiology, Martin Luther University, Halle, GDR.
Vereecke
J
J
Carmeliet
E
E
D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D015222:Sodium Channels / Q000378:metabolism*; D013237:Stereoisomerism
D010879:Piperazines; D015222:Sodium Channels; C046261:DPI 201-106