Publication Date:
1998-03-07
Description:
The tetrodotoxin-sensitive sodium ion (Na+) channel is opened by cellular depolarization and favors the passage of Na+ over other ions. Activation of the beta-adrenergic receptor or protein kinase A in rat heart cells transformed this Na+ channel into one that is promiscuous with respect to ion selectivity, permitting calcium ions (Ca2+) to permeate as readily as Na+. Similarly, nanomolar concentrations of cardiotonic steroids such as ouabain and digoxin switched the ion selectivity of the Na+ channel to this state of promiscuous permeability called slip-mode conductance. Slip-mode conductance of the Na+ channel can contribute significantly to local and global cardiac Ca2+ signaling and may be a general signaling mechanism in excitable cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Santana, L F -- Gomez, A M -- Lederer, W J -- New York, N.Y. -- Science. 1998 Feb 13;279(5353):1027-33.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Medical Biotechnology Center and School of Medicine, University of Maryland, 725 West Lombard Street, Baltimore, MD 21201, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9461434" target="_blank"〉PubMed〈/a〉
Keywords:
Action Potentials
;
Animals
;
Calcium/*metabolism
;
Cardiotonic Agents/pharmacology
;
Cyclic AMP/metabolism
;
Cyclic AMP-Dependent Protein Kinases/metabolism
;
Digoxin/pharmacology
;
Enzyme Activation
;
In Vitro Techniques
;
Ion Channel Gating
;
Isoproterenol/pharmacology
;
Myocardial Contraction/*physiology
;
Myocardium/cytology/*metabolism
;
Ouabain/pharmacology
;
Patch-Clamp Techniques
;
Rats
;
Receptors, Adrenergic, beta/physiology
;
Ryanodine Receptor Calcium Release Channel/metabolism
;
Sarcoplasmic Reticulum/*metabolism
;
Signal Transduction
;
Sodium/metabolism
;
Sodium Channel Blockers
;
Sodium Channels/drug effects/*metabolism
;
Sodium-Calcium Exchanger/metabolism
;
Tetrodotoxin/pharmacology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
