Differential Expression and Remodeling of Transient Outward Potassium Currents in Human Left Ventricles.

Background: Myocardial, transient, outward currents, , have been shown to play pivotal roles in action potential (AP) repolarization and remodeling in animal models. The properties and contribution of to left ventricular (LV) repolarization in the human heart, however, are poorly defined.

Methods And Results: Whole-cell, voltage-clamp recordings, acquired at physiological (35°C to 37°C) temperatures, from myocytes isolated from the LV of nonfailing human hearts identified 2 distinct transient currents, () and (), with significantly (<0.

Modulation of BK channels contributes to activity-dependent increase of excitability through MTORC1 activity in CA1 pyramidal cells of mouse hippocampus.

Memory acquisition and synaptic plasticity are accompanied by changes in the intrinsic excitability of CA1 pyramidal neurons. These activity-dependent changes in excitability are mediated by modulation of intrinsic currents which alters the responsiveness of the cell to synaptic inputs. The afterhyperpolarization (AHP), a major contributor to the regulation of neuronal excitability, is reduced in animals that have acquired several types of hippocampus-dependent memory tasks and also following synaptic potentiation by high frequency stimulation.