Search

Research was conducted to examine the transmural heterogeneity of action potentials and I(sub to1) in myocytes isolated from the human right ventricle. Results reveal that M cells are present in the right ventricle in humans and that a gradient of I(sub to1) is present in cells across the human right ventricular wall from the endocardium to the epicardium. Findings show important transmural heterogeneity in the action potential and I(sub to1) properties pointing to an important clinical implication in human cardiac electrophysiology.

Isolation of cells by chunk and perfusion methods reveals that the transient outward K+ current, (Ito1), Ca2+ dependent Cl- current, (Ito2), and the delayed rectifier K+ current, (Ik), are found in the dog atrium. Ik is more sensitive to the isolation method than Ito1 or Ito2. The properties of Ito1 and Ik repolarizing currents of the dog atrium are similar to those in the human atrium. These studies help in the in vivo and in vitro analysis of canine atrial electrophysiology.

Evaluates the heterogeneity of cardiac action potential (AP), transient potassium efflux current and influx current of potassium in the right ventricle of the human heart. Details on cardiac electrophysiology; Methodology of the study; Results of the study.

The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca(2+)-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca(2+) entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases., (Copyright © 2015 the American Physiological Society.)