Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Editor

Personal info

View

About

Terms

Javascript disabled

Please enable Javascript support in your browser to use this application.

Instructions on how to enable JavaScript on different browsers can be found here: http://www.google.com/support/bin/answer.py?answer=23852.

[edit this page]

Cameron, J.S. et al.

Effects of epinephrine on automaticity and the incidence of arrhythmias in Purkinje fibers surviving myocardial infarction.

The role of the sympathetic nervous system in the development of late-phase ventricular arrhythmias occurring 24 hr after myocardial infarction was investigated using canine ventricular preparations in vitro. One day after two-stage ligation of the left anterior descending coronary artery, transmembrane action potentials from subendocardial Purkinje fibers were monitored in noninfarcted (NZ) and infarcted (IZ) zones during Tyrode's superfusion at 37 degrees C. In combined preparations incorporating both NZ and IZ, epinephrine (10(-7)-10(-5)M) produced dose-dependent increases in spontaneous rates of depolarization, slope of phase 4 depolarization and incidence of spontaneous and induced arrhythmias. In particular, premature electrical stimulation induced increased numbers of unstimulated responses or rapid, repetitive depolarizations. These responses to the drug were antagonized by propranolol (10(-6)M) but not phentolamine (10(-7)M). Epinephrine appeared to promote the functional dissociation of conducted impulses often observed in the IZ of combined preparations. In preparations excised from either NZ or IZ alone, epinephrine induced elevated spontaneous firing rates, particularly in the IZ, but no increase in arrhythmias. These data suggest that elevated levels of beta adrenergic receptor stimulation 24 hr after myocardial infarction may increase ventricular vulnerability to arrhythmias arising through enhanced automaticity or reentry.[1]

References

Effects of epinephrine on automaticity and the incidence of arrhythmias in Purkinje fibers surviving myocardial infarction. Cameron, J.S., Han, J. J. Pharmacol. Exp. Ther. (1982) [Pubmed]

Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenes Open Access Licence Privacy Policy Terms of Use apsburg

The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.