Linked Life Data

3256422

Source:http://linkedlifedata.com/resource/pubmed/id/3256422

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1989-10-17
pubmed:abstractText
The purpose of these experiments was to study the pharmacological response of quinidine induced early afterdepolarisations to gain insights into underlying ionic mechanisms. Quinidine (8.5 microM) induced stable early afterdepolarisations at low activation frequencies in 80% of canine cardiac Purkinje fibres superfused with a modified Tyrode's solution. Early afterdepolarisations arose from a secondary plateau in the voltage range of -30 to -60 mV. Calcium channel blockers (verapamil, 1 microM, in 3/6 preparations; verapamil, 10 microM in 6/6 preparations; nifedipine, 0.1 microM in 5/5 preparations) completely eliminated early afterdepolarisations, despite continued quinidine superfusion, without altering the underlying action potential. Isoprenaline (0.2-1 microM) restored them in 75% of these preparations during continued calcium blocker superfusion. Tetrodotoxin (5/5 preparations) eliminated early afterdepolarisations by abbreviating action potentials and reducing or eliminating the quinidine induced secondary plateau. While low concentrations of isoprenaline favoured the occurrence of early afterdepolarisations, larger concentrations eliminated them by enhancing spontaneous automaticity. These experiments suggest that voltage dependent and/or receptor regulated slow inward current plays an important role in quinidine induced early afterdepolarisations. Beta receptor stimulation can enhance or suppress early afterdepolarisations, depending on whether effects on slow inward current (tending to favour them) or on automaticity (suppressing them) predominate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0008-6363
pubmed:author
pubmed:issnType
Print
pubmed:volume
22
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
808-17
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Pharmacological response of quinidine induced early afterdepolarisations in canine cardiac Purkinje fibres: insights into underlying ionic mechanisms.
pubmed:affiliation
Department of Pharmacology, McGill University, Montreal, Quebec, Canada.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't