Itsuo Kodama

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AIMS Atrial dilatation and myocardial stretch are strongly associated with atrial fibrillation (AF). However, the mechanisms by which the three-dimensional (3D) atrial architecture and heterogeneous stretch contribute to AF perpetuation are incompletely understood. We compared AF dynamics during stretch-related AF (pressure: 12 cmH(2)O) in normal sheep(More)
Gprotein-activated inwardly rectifying K+ channel (GIRK or Kir3) currents are inhibited by mechanical stretch of the cell membrane, but the underlying mechanisms are not understood. In Xenopus oocytes heterologously expressing GIRK channels, membrane stretch induced by 50% reduction of osmotic pressure caused a prompt reduction of GIRK1/4, GIRK1, and GIRK4(More)
Membrane-embedded voltage-sensor domains in voltage-dependent potassium channels (K(v) channels) contain an impressive number of charged residues. How can such highly charged protein domains be efficiently inserted into biological membranes? In the plant K(v) channel KAT1, the S2, S3, and S4 transmembrane helices insert cooperatively, because the S3, S4,(More)
T-type Ca2+ channels are implicated in cardiac automaticity, cell growth, and cardiovascular remodeling. Two voltage-gated Ca2+ subtypes (Ca(v)3.1 and Ca(v)3.2) have been cloned for the pore-forming alpha(1)-subunit of the T-type Ca2+ channel in cardiac muscle, but their differential roles remain to be clarified. The aim of this study was to elucidate the(More)
Molecular signaling of cardiac autonomic innervation is an unresolved issue. Here, we show that glial cell line-derived neurotrophic factor (GDNF) promotes cardiac sympathetic innervation in vitro and in vivo. In vitro, ventricular myocytes (VMs) and sympathetic neurons (SNs) isolated from neonatal rat ventricles and superior cervical ganglia were cultured(More)
The sinoatrial node (SAN) is heterogeneous in terms of cell size, ion channels, current densities, connexins and electrical coupling. For example, Nav1.5 (responsible for INa) and Cx43 (responsible for electrical coupling) are absent from the centre of the SAN (normally the leading pacemaker site), but present in the periphery (at SAN-atrial muscle(More)
Molecular signaling of sympathetic innervation of myocardium is an unresolved issue. The purpose of this study was to investigate the effect of neurotrophic factors on sympathetic neurite growth towards cardiomyocytes. Cardiomyocytes (CMs) and sympathetic neurons (SNs) were isolated from neonatal rat hearts and superior cervical ganglia, and were(More)
To elucidate the subcellular mechanism underlying the aftereffects of high-intensity dc shocks, a small pore, which mimics reversible breakdown of the cell membrane (electroporation), was incorporated into the phase-2 Luo-Rudy (L-R) model of ventricular action potentials. The pore size was set to occupy 0.15%-4.25% of the total cell membrane during the(More)
The aim of myocardial tissue engineering is to repair or regenerate damaged myocardium with engineered cardiac tissue. However, this strategy has been hampered by lack of functional integration of grafts with native myocardium. Autonomic innervation may be crucial for grafts to function properly with host myocardium. In this study, we explored the(More)
  • Mari Amino, Koichiro Yoshioka, Teruhisa Tanabe, Etsuro Tanaka, Hidezo Mori, Yoshiya Furusawa +7 others
  • 2006
OBJECTIVE Radiation has been shown to enhance intercellular communication in the skin and lungs through an increase of connexin43 (Cx43) expression. If analogous Cx43 up-regulation is induced in the diseased heart, it would provide a new perspective in radiation therapy for arrhythmias. The aim of the present study is to test this hypothesis. METHODS(More)