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Titolo:
EFFECT OF GADOLINIUM ON STRETCH-INDUCED CHANGES IN CONTRACTION AND INTRACELLULARLY RECORDED ACTIONPOTENTIAL AND AFTERPOTENTIAL OF RAT ISOLATED ATRIUM
Autore:
TAVI P; LAINE M; WECKSTROM M;
Indirizzi:
UNIV OULU,DEPT PHYSIOL,KAJAANINTIE 52A SF-90220 OULU FINLAND UNIV OULU,DEPT PHYSIOL SF-90220 OULU FINLAND UNIV OULU,BIOCTR OULU SF-90220 OULU FINLAND
Titolo Testata:
British Journal of Pharmacology
fascicolo: 2, volume: 118, anno: 1996,
pagine: 407 - 413
SICI:
0007-1188(1996)118:2<407:EOGOSC>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
PIG VENTRICULAR MYOCYTES; CARDIAC PURKINJE-FIBERS; ACTIVATED ION CHANNELS; TRANSIENT INWARD CURRENT; CULTURED CHICK HEART; GUINEA-PIG; INDUCED ARRHYTHMIAS; CALCIUM TRANSIENTS; ACTION-POTENTIALS; GENE-EXPRESSION;
Keywords:
GADOLINIUM; STRETCH; MYOCYTE; ELECTROPHYSIOLOGY; CONTRACTION; ACTION POTENTIAL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
48
Recensione:
Indirizzi per estratti:
Citazione:
P. Tavi et al., "EFFECT OF GADOLINIUM ON STRETCH-INDUCED CHANGES IN CONTRACTION AND INTRACELLULARLY RECORDED ACTIONPOTENTIAL AND AFTERPOTENTIAL OF RAT ISOLATED ATRIUM", British Journal of Pharmacology, 118(2), 1996, pp. 407-413

Abstract

1 Atrial arrhythmias, like atrial fibrillation and extrasystoles, arecommon in clinical situations when atrial pressure is increased. Although cardiac mechanoelectrical feedback has been under intensive studyfor many years, the mechanisms of stretch-induced arrhythmias are notknown in detail. This is partly due to methodological difficulties inrecording intracellular voltage during stretch stimulation. In this study we investigated the effects of gadolinium (Gd3+), a blocker of stretch-activated (SA) channels, on stretch-induced changes in rat atrial action potentials and contraction force. 2 By intracellular voltage recordings from rat isolated atria we studied the effects of Gd3+ (80 mu M) on stretch-induced changes in action potentials. The stretch wasinduced by increasing pressure inside the atrium (1 mmHg to 7 mmHg). An elastic electrode holder that moved along the atrial tissue was used in the recordings. Thus the mechanical artifacts were eliminated andthe cell-electrode contact was made more stable. To examine the influence of Gd3+ on atrial contraction we stretched the atria at differentdiastolic pressure levels (1 to 7 mmHg) with Gd3+ application of (80 mu M) or diltiazem (5.0 mu M). Contraction force was monitored by recording the pressure changes generated by the atrial contractions. 3 Ourresults show that: (1) atrial stretch induces delayed afterdepolarizations (DADs), increase in action potential amplitude and increase in relative conduction speed; (ii) Gd3+ blocks stretch-induced DADs and action potential changes; (iii) Gd3+ inhibits pressure-stimulated increase in the atrial contraction force, while similar inhibition is not observed with diltiazem, a blocker of L-type calcium channels. 4 This study suggests that Gd3+ inhibits stretch-induced changes in cell electrophysiology and contraction in the rat atrial cells and that the effects of gadolinium are due to rather specific block of stretch-activatedion channels with only a small effect on voltage-activated calcium channels.

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Documento generato il 01/12/20 alle ore 22:57:08