Distribution of a persistent sodium current across the ventricular wall in guinea pigs.
A tetrodotoxin-sensitive persistent sodium current, I(pNa), was found in guinea pig ventricular myocytes by whole-cell patch clamping. This current was characterized in cells derived from the basal left ventricular subendocardium, midmyocardium, and subepicardium. Midmyocardial cells show a statistically significant (P<0.05) smaller I(pNa) than subendocardial and subepicardial myocytes. There was no significant difference in I(pNa) current density between subepicardial and subendocardial cells. Computer modeling studies support a role of this current in the dispersion of action potential duration across the ventricular wall.
Sakmann
B F
BF
University Laboratory of Physiology, Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK.
Spindler
A J
AJ
Bryant
S M
SM
Linz
K W
KW
Noble
D
D
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D003198:Computer Simulation; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D018021:Lithium Chloride / Q000494:pharmacology; D008955:Models, Cardiovascular; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009928:Organ Specificity / Q000502:physiology; D018408:Patch-Clamp Techniques; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology
D015220:Calcium Channels; D015222:Sodium Channels; D019831:Sodium-Calcium Exchanger; D002104:Cadmium; D013779:Tetrodotoxin; D012964:Sodium; D018021:Lithium Chloride