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Science 24 June 1988:
Vol. 240. no. 4860, pp. 1782 - 1783
DOI: 10.1126/science.2454511
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Articles

Science, Vol 240, Issue 4860, 1782-1783
Copyright © 1988 by American Association for the Advancement of Science

articles

The alpha subunit of the GTP binding protein activates muscarinic potassium channels of the atrium

E Cerbai, U Klockner, and G Isenberg

Department of Applied Physiology, University of Cologne, Koln, FRG.

It has been debated whether the potassium channel of the atrium is activated by the alpha subunit or by the beta gamma subunits of guanine nucleotide binding (G) proteins, which dissociate on activation with guanosine triphosphate (GTP). Therefore, the channel-activating effectiveness of these subunits on isolated guinea pig atrial cells was tested. The activated alpha K subunit from human erythrocytes activated the channel in subpicomolar concentrations. The beta gamma dimer from bovine brain activated the channel in nanomolar concentrations. These results support the view that, physiologically, the alpha subunit activates the channel.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Isoprenaline can activate the acetylcholine-induced K+ current in canine atrial myocytes via Gs-derived {beta}{gamma} subunits.
S. Sorota, I. Rybina, A. Yamamoto, and X.-Y. Du (1999)
J. Physiol. 514, 413-423
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ATP-Dependent Activation of the Atrial Acetylcholine-Induced K+ Channel Does Not Require Nucleoside Diphosphate Kinase Activity.
S. Sorota, M. Chlenov, X.-Y. Du, and M. Kagan (1998)
Circ. Res. 82, 971-979
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Cardiac Muscarinic Potassium Channel Activity Is Attenuated by Inhibitors of Gß{gamma}.
L. A. Nair, J. Inglese, R. Stoffel, W. J. Koch, R. J. Lefkowitz, M. M. Kwatra, and A. O. Grant (1995)
Circ. Res. 76, 832-838
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