Linked Life Data

19429824

Source:http://linkedlifedata.com/resource/pubmed/id/19429824

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2009-6-30
pubmed:abstractText
Ectopic activity in cardiac muscle within pulmonary veins (PVs) is associated with the onset and the maintenance of atrial fibrillation in humans. The mechanism underlying this ectopic activity is unknown. Here we investigate automatic activity generated by catecholaminergic stimulation in the rat PV. Intracellular microelectrodes were used to record electrical activity in isolated strips of rat PV and left atrium (LA). The resting cardiac muscle membrane potential was lower in PV [-70 +/- 1 (SE) mV, n = 8] than in LA (-85 +/- 1 mV, n = 8). No spontaneous activity was recorded in PV or LA under basal conditions. Norepinephrine (10(-5) M) induced first a hyperpolarization (-8 +/- 1 mV in PV, -3 +/- 1 mV in LA, n = 8 for both) then a slowly developing depolarization (+21 +/- 2 mV after 15 min in PV, +1 +/- 2 mV in LA) of the resting membrane potential. Automatic activity occurred only in PV; it was triggered at approximately -50 mV, and it occurred as repetitive bursts of slow action potentials. The diastolic membrane potential increased during a burst and slowly depolarized between bursts. Automatic activity in the PV was blocked by either atenolol or prazosine, and it could be generated with a mixture of cirazoline and isoprenaline. In both tissues, cirazoline (10(-6) M) induced a depolarization (+37 +/- 2 mV in PV, n = 5; +5 +/- 1 mV in LA, n = 5), and isoprenaline (10(-7) M) evoked a hyperpolarization (-11 +/- 3 mV in PV, n = 7; -3 +/- 1 mV in LA, n = 6). The differences in membrane potential and reaction to adrenergic stimulation lead to automatic electrical activity occurring specifically in cardiac muscle in the PV.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1522-1539
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
297
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H102-8
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Catecholaminergic automatic activity in the rat pulmonary vein: electrophysiological differences between cardiac muscle in the left atrium and pulmonary vein.
pubmed:affiliation
Centre National de la Recherche Scientifique FRE 3092, Faculté des Sciences, Université François-Rabelais, Tours, France.
pubmed:publicationType
Journal Article, In Vitro