Novel Mechanism of Transient Outward Potassium Channel Current Regulation in the Heart

Novel mechanism of transient outward potassium channel current regulation in the heart: implications for cardiac electrophysiology in health and disease.

Transient outward potassium current in ICC.

Interstitial cells of Cajal (ICC) are the pacemakers of the gut, initiating slow-wave activity. Several ion channels have been identified that contribute to the depolarization phase of the slow wave. Our aim was to contribute to knowledge about the identity and role of ICC potassium channels in pacemaking. Here we describe a transient outward potassium current in cell-attached patches of ICC. T...

Effects of allitridum on the transient outward potassium current in rats with heart failure

OBJECTIVE To study the effect of allitridum on the transient outward potassium current (Ito) of ventricular myocytes in heart failure (HF). METHODS The dual enzymatic method was used to separate single ventricular myocytes from Sprague Dawley rats. Patch-clamping was used to record Ito and analyze the effect of allitridum on the current. RESULTS The Ito current had a significant decrease in...

Transient outward potassium current and Ca2+ homeostasis in the heart: beyond the action potential.

The present review deals with Ca2+-independent, K+-carried transient outward current (Ito), an important determinant of the early repolarization phase of the myocardial action potential. The density of total Ito and of its fast and slow components (I(to,f) and I(to,s), respectively), as well as the expression of their molecular correlates (pore-forming protein isoforms Kv4.3/4.2 and Kv1.4, resp...

Transient Outward Potassium Channels Dependence on Channel Inactivation Mechanisms

We carried out a systematic study on the effects of elevating [K]O on the properties of a transient outward potassium channel encoded by a cardiac cDNA (RHKI) and compared them with those on two Shaker potassium channels (H-4 and H-37). The amino acid sequences of all three channels are known, and their structure-function relations have been partially characterized. All three channels were expr...