Minor contribution of cytosolic Ca transients to the pacemaker rhythm in guinea pig sinoatrial node cells
نویسندگان
چکیده
Yukiko Himeno, Futoshi Toyoda, Hiroyasu Satoh, Akira Amano, Chae Young Cha, Hiroshi Matsuura, and Akinori Noma Department of Diabetes and Clinical Nutrition, Faculty of Medicine, Kyoto University, Kyoto; Department of Physiology, Faculty of Medicine, Shiga University of Medical Science, Shiga; Department of Pharmacology, Faculty of Medicine, Nara Medical University, Nara; and Department of Biosimulation, College of Life Sciences, Ritsumeikan University, Kusatsu, Japan
منابع مشابه
Minor contribution of cytosolic Ca2+ transients to the pacemaker rhythm in guinea pig sinoatrial node cells.
The question of the extent to which cytosolic Ca(2+) affects sinoatrial node pacemaker activity has been discussed for decades. We examined this issue by analyzing two mathematical pacemaker models, based on the "Ca(2+) clock" (C) and "membrane clock" (M) hypotheses, together with patch-clamp experiments in isolated guinea pig sinoatrial node cells. By applying lead potential analysis to the mo...
متن کاملComparison of Hyperpolarization-Activiated Current “if ” on the Rate of Spontaneous Activity and Cycle Length before and after Cutting of Atrial Muscle away from Intact Sinoatrial Node of Rabbit
It has been shown that the hyperpolarization-activated current “if” that is blocked by 2 mM Cs+ plays a minor role on pacemaker activity of the center and a major role on activity of the periphery of rabbit intact sino-atrial node. On the other hand some investigations showed that if the atrial muscle, surrounding the sino-atrial node, is cut away there is a shift in leading pacemaker site from...
متن کاملDirect negative chronotropic action of desflurane on sinoatrial node pacemaker activity in the guinea pig heart.
BACKGROUND Desflurane inhalation is associated with sympathetic activation and concomitant increase in heart rate in humans and experimental animals. There is, however, little information concerning the direct effects of desflurane on electrical activity of sinoatrial node pacemaker cells that determines the intrinsic heart rate. METHODS Whole-cell patch-clamp experiments were conducted on gu...
متن کاملSustained inward current during pacemaker depolarization in mammalian sinoatrial node cells.
Several time- and voltage-dependent ionic currents have been identified in cardiac pacemaker cells, including Na(+) current, L- and T-type Ca(2+) currents, hyperpolarization-activated cation current, and various types of delayed rectifier K(+) currents. Mathematical models have demonstrated that spontaneous action potentials can be reconstructed by incorporating these currents, but relative con...
متن کاملRegulation of L-type calcium channel and delayed rectifier potassium channel activity by p21-activated kinase-1 in guinea pig sinoatrial node pacemaker cells.
Phosphorylation of ion channels plays an important role in the regulation of cardiac function, but signaling mechanisms controlling dephosphorylation are not well understood. We have tested the hypothesis that p(21)-activated kinase-1 (Pak1), a serine-threonine protein kinase regulated by Ras-related small G proteins, regulates sinoatrial node (SAN) ion channel activity through a mechanism invo...
متن کامل