Linked Life Data

6149823

Source:http://linkedlifedata.com/resource/pubmed/id/6149823

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1984-12-28
pubmed:abstractText
We studied the ability of alpha-adrenergic stimulation to induce delayed afterdepolarizations and triggered activity in Purkinje fibers from cat hearts in the presence of an elevated Ca++ concentration. Delayed afterdepolarizations could not be induced at drive cycle lengths of 200 to 500 msec in the presence of extracellular Ca++ concentrations of 2.7 to 8.1 mM. However, the addition of 10(-5)M phenylephrine in the presence of 5 X 10(-7)M propranolol elicited delayed afterdepolarizations in eight of 10 preparations at a Ca++ concentration of 8.1 mM; nondrive-triggered action potentials were recorded from three of the preparations. These afterpotentials were completely suppressed by 5 X 10(-7)M prazosin or 10(-6)M phentolamine. In the presence of 5 X 10(-7)M propranolol, 10(-5)M phenylephrine prolonged action potential duration and this effect was suppressed by 5 X 10(-7)M prazosin. Methoxamine, at a concentration of 5 X 10(-6)M, was also observed to potentiate delayed afterdepolarizations in all of three preparations studied. These results demonstrate that alpha-adrenergic stimulation can induce afterpotentials in the presence of elevated Ca++ levels in cat hearts. Stimulation of alpha-adrenoceptors may be responsible for arrhythmias under Ca++-loaded conditions such as ischemia and coronary reperfusion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0009-7322
pubmed:author
pubmed:issnType
Print
pubmed:volume
70
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1074-82
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Delayed afterdepolarizations and triggered activity induced in feline Purkinje fibers by alpha-adrenergic stimulation in the presence of elevated calcium levels.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't