Publication Date:
1989-08-04
Description:
The signaling pathways by which beta-adrenergic agonists modulate voltage-dependent cardiac sodium currents are unknown, although it is likely that adenosine 3'5'-monophosphate (cAMP) is involved. Single-channel and whole-cell sodium currents were measured in cardiac myocytes and the signal transducing G protein Gs was found to couple beta-adrenergic receptors to sodium channels by both cytoplasmic (indirect) and membrane-delimited (direct) pathways. Hence, Gs can act on at least three effectors in the heart: sodium channels, calcium channels, and adenylyl cyclase. The effect on sodium currents was inhibitory and was enhanced by membrane depolarization. During myocardial ischemia the sodium currents of depolarized cells may be further inhibited by the accompanying increase in catecholamine levels.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schubert, B -- VanDongen, A M -- Kirsch, G E -- Brown, A M -- DK19319/DK/NIDDK NIH HHS/ -- HL36930/HL/NHLBI NIH HHS/ -- HL39262/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1989 Aug 4;245(4917):516-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2547248" target="_blank"〉PubMed〈/a〉
Keywords:
8-Bromo Cyclic Adenosine Monophosphate/pharmacology
;
Animals
;
Cyclic AMP/physiology
;
Electric Conductivity
;
GTP-Binding Proteins/*physiology
;
Guanosine 5'-O-(3-Thiotriphosphate)
;
Guanosine Triphosphate/analogs & derivatives/pharmacology
;
Heart/drug effects/*physiology
;
Isoproterenol/pharmacology
;
Potassium Channels/physiology
;
Rats
;
Receptors, Adrenergic, beta/*physiology
;
Signal Transduction
;
Sodium Channels/*physiology
;
Thionucleotides/pharmacology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
