title: Relationship between steady-state activation and availability of cardiac sodium channel: evidence of uncoupling.
abstract: The coupling between steady-state activation and availability from inactivation was characterized for the cardiac Na+ channel. To evaluate this coupling, we plotted the relationship between the conductance and availability curve midpoint potentials measured in 92 rat ventricular cardiomyocytes and applied a correlation analysis. We found a high correlation between the midpoints (correlation coefficient = 0.86, slope = 0.95) within the availability midpoint potential range positive to -100 mV. In contrast, the midpoints were not correlated in the myocytes (37 of 92 cells) having midpoint potential negative to -100 mV, indicating an uncoupling between activation and availability.
authors.affiliation: Department of Medicine, Henry Ford Heart Heart and Vascular Institute, Detroit, Michigan 48202-2689, USA.
authors.forename: V A
authors.initials: VA
authors.lastname: Maltsev
authors.forename: A I
authors.initials: AI
authors.lastname: Undrovinas
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004553:Electric Conductivity; D004594:Electrophysiology; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D015222:Sodium Channels / Q000502:physiology*; D016276:Ventricular Function
chemical_list: D015222:Sodium Channels