Characteristics of the ventricular transient outward potassium current in genetic rodent models of diabetes.
The whole-cell configuration of the patch-clamp technique was employed to measure the transient outward potassium current in enzymatically isolated ventricular cells of spontaneously diabetic rats (BB/Wor) and mice (ob/ob). Healthy littermates (non-diabetic BB rats and lean mice) were used as controls. There was no significant difference between the non-diabetic and diabetic BB rats (Type I diabetes, IDDM) in the amplitude of either the current measured in the absence or the one found in the presence of 4-aminopyridine. The voltage dependence of the activation and steady-state inactivation was also similar in both populations, as no significant difference was observed in the rate of recovery from inactivation of Ito. The amplitudes of the total and 4-aminopyridine sensitive currents of lean and obese mice (Type II diabetes, NIDDM) were also similar. The voltage dependences of the activation and of the steady-state inactivation did not differ significantly, either. Our results might indicate certain limitations of the applicability of experiments carried out on genetically diabetic rats if the results are compared to those derived from the healthy littermates as controls.
Rusznák
Z
Z
Department of Physiology, University Medical School of Debrecen, Hungary. rz@phys.dote.hu
Cseresnyés
Z
Z
Sipos
I
I
Magyar
J
J
Kovács
L
L
Szücs
G
G
D000818:Animals; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000503:physiopathology; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000503:physiopathology*; D006321:Heart / Q000502:physiology / Q000503:physiopathology*; D006352:Heart Ventricles; D008564:Membrane Potentials; D051379:Mice; D008820:Mice, Obese; D009765:Obesity; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D011913:Rats, Inbred BB; D013851:Thinness
D015221:Potassium Channels