DSpace About DSpace Software 日本語
 

GINMU >
01 奈良県立医科大学 >
011 医学部 >
0112 紀要 >
01121 Journal of Nara Medical Association >
Vol.45 No.4 >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10564/1636

Title: CALCIUM MODULATION OF THE SPONTANEOUS ACTIVITY AND THE IONIC CURRENTS IN RABBIT ATRIO-VENTRICULAR NODAL CELLS
Authors: Satoh, Hiroyasu
Nario, Kazuhiko
Narushima, Itaru
Keywords: Ca²⁺ concentration
spontaneous activity
ionic currents
voltage-clamp
atrio-ventricular nodal cells
Issue Date: 31-Aug-1994
Publisher: 奈良医学会
Citation: 奈良医学雑誌 Vol.45 No.4 p.333-340
Abstract: Modulation by changing the extracellular Ca²⁺ concentration ([Ca]ₒ) of the electrophysiological activity in isolated rabbit atrio-ventricular (AV) nodal cells was investigated using the two-microelectrode voltage-clamp technique. Low [Ca]ₒ (0.9 mM or Ca²⁺-free) decreased the rate of spontaneous beating, but the maximum rate of depolarization was significantly enhanced. Simultaneously, the [Ca]ₒ decline tended to increase the action potential amplitude, prolong the action potential duration (at 50% repolarization), and shorten the cycle length. The maximum diastolic potential was hyperpolarized. But these factors were not significant. In contrast, elevation of [Ca]ₒ to 5.4 or 10 mM (from 1.8 mM) transiently stimulated, but then inhibited the spontaneous activity. The effects on the action potential parameters were rather depressant. In voltage-clamp experiments, the [Ca]ₒ elevation increased the maximum onductances for the slow inward current and the delayed outward K⁺ current, whereas the [Ca]ₒ decline decreased them. An arrhythmia occurred in 4 out of 6 preparations only at 10 mM [Ca]ₒ. These results indicate that [Ca]ₒ would modulate the electrical activity of the AV nodal cells due to conductance changes in the ionic channels, but high [Ca]ₒ induces rather the depressant effects.
URI: http://hdl.handle.net/10564/1636
ISSN: 04695550
13450069
Appears in Collections:Vol.45 No.4

Files in This Item:

File Description SizeFormat
333-340p:CALCIUM_MODULATION_OF_THE_SPONTANEOUS_ACTIVITY_AND_THE_IONIC_CURRENTS_IN_RABBIT_ATRIO-VENTRICULAR_NODAL_CELLS.pdf684.11 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback