AJP - Heart Calcium Transients and Cell-Sarcomere
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Heart Circ Physiol 276: H1559-H1566, 1999;
0363-6135/99 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wang, W.
Right arrow Articles by Ochi, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wang, W.
Right arrow Articles by Ochi, R.
Vol. 276, Issue 5, H1559-H1566, May 1999

Properties and expression of Ca2+-activated K+ channels in H9c2 cells derived from rat ventricle

Wei Wang1, Makino Watanabe1, Takeshi Nakamura2, Yoshihisa Kudo2, and Rikuo Ochi1

1 Department of Physiology, Juntendo University School of Medicine, Tokyo 113-8421; and 2 Laboratory of Cellular Neurobiology, School of Life Science, Tokyo University of Pharmacy and Life Science, Tokyo 192-03, Japan

H9c2 is a clonal myogenic cell line derived from embryonic rat ventricle that can serve as a surrogate for cardiac or skeletal muscle in vitro. Using whole cell clamp with H9c2 myotubes, we observed that depolarizing pulses activated slow outward K+ currents and then slow tail currents. The K+ currents were abolished in a Ca2+-free external solution, indicating that they were Ca2+-activated K+ currents. They were blocked by apamin, a small-conductance Ca2+-activated K+ (SK) channel antagonist (IC50 = 6.2 nM), and by d-tubocurarine (IC50 = 49.4 µM). Activation of SK channels exhibited a bell-shaped voltage dependence that paralleled the current-voltage relation for L-type Ca2+ currents (ICa,L). ICa,L exhibited a slow time course similar to skeletal ICa,L, were unaffected by apamin, and were only slightly depressed by d-tubocurarine. RT-PCR analysis of the mRNAs revealed that rSK3, but not rSK1 or rSK2, was expressed in H9c2 myotubes but not in myoblasts. These results suggest that rSK3 channels are expressed in H9c2 myotubes and are primarily activated by ICa,L directly or indirectly via Ca2+-induced Ca2+ release from sarcoplasmic reticulum.

SK channels; L-type calcium channels; apamin; d-tubocurarine; reverse transcriptase-polymerase chain reaction


This article has been cited by other articles:


Home page
 J. Physiol.Home page
S. Nattel
Calcium-activated potassium current: a novel ion channel candidate in atrial fibrillation
J. Physiol., April 1, 2009; 587(7): 1385 - 1386.
[Full Text] [PDF]

Home page
 J. Pharmacol. Exp. Ther.Home page
S. A. Gupte, K.-X. Li, T. Okada, K. Sato, and M. Oka
Inhibitors of Pentose Phosphate Pathway Cause Vasodilation: Involvement of Voltage-Gated Potassium Channels
J. Pharmacol. Exp. Ther., April 1, 2002; 301(1): 299 - 305.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
E. T. Barfod, A. L. Moore, and S. D. Lidofsky
Cloning and functional expression of a liver isoform of the small conductance Ca2+-activated K+ channel SK3
Am J Physiol Cell Physiol, April 1, 2001; 280(4): C836 - C842.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. Rev.Home page
O. M. Sejersted and G. Sjogaard
Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise
Physiol Rev, October 1, 2000; 80(4): 1411 - 1481.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online