Three different gating models for inactivation of the Ito in ventricular myocytes of rats and mice.
Kinetic models to describe the time course of the Ca(2+)-independent outward potassium current (Ito) in cardiac ventricular cells were constructed. The Ito traces were recorded from isolated myocytes of rats and mice using the whole-cell configuration of the patch-clamp technique. An iterative method was developed to eliminate the capacitive transient overlapping the early part of the Ito. The isolated Ito curves were then fitted by Hodgkin-Huxley type functions and different inactivation gating mechanisms were identified in various groups of the animals. In some Wistar rats a single inactivation route was found. Another group of Wistar rats and diabetic BB/Mol rats showed two independent inactivation pathways both of which resulted in a completely closed channel. In lean specimen of C-57 mice and in streptozotocin-treated Wistar rats the two inactivation gates gave closed channels only when both parallel inactivating transitions have been completed. In this case a possible interaction between the gating particles has been revealed.
Cseresnyés
Z
Z
Department of Physiology, Medical University School of Debrecen, Hungary.
Rusznák
Z
Z
Bozsányi
A
A
Magyar
J
J
Szücs
G
G
Kovács
L
L
D000818:Animals; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D005260:Female; D006321:Heart / Q000502:physiology* / Q000503:physiopathology; D006352:Heart Ventricles; D015640:Ion Channel Gating; D007700:Kinetics; D008297:Male; D008433:Mathematics; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D011913:Rats, Inbred BB; D017208:Rats, Wistar
D015221:Potassium Channels