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Titolo:
Stretch and quick release of rat cardiac trabeculae accelerates Ca2+ wavesand triggered propagated contractions
Autore:
Wakayama, Y; Miura, M; Sugai, Y; Kagaya, Y; Watanabe, J; Ter Keurs, HEDJ; Shirato, K;
Indirizzi:
Tohoku Univ, Grad Sch Med, Dept Cardiovasc Med, Aoba Ku, Sendai, Miyagi 9808574, Japan Tohoku Univ Sendai Miyagi Japan 9808574 Ku, Sendai, Miyagi 9808574, Japan Univ Calgary, Dept Med, Calgary, AB T2N 4M1, Canada Univ Calgary Calgary AB Canada T2N 4M1 t Med, Calgary, AB T2N 4M1, Canada
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 5, volume: 281, anno: 2001,
pagine: H2133 - H2142
SICI:
0363-6135(200111)281:5<H2133:SAQROR>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTIVATED ION CHANNELS; FERRET VENTRICULAR MUSCLE; INTRACELLULAR CALCIUM; MECHANOELECTRICAL FEEDBACK; INDUCED ARRHYTHMIAS; SARCOMERE-LENGTH; TENSION; HEART; TRANSIENTS; MECHANISMS;
Keywords:
arrhythmias;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Shirato, K Tohoku Univ, Grad Sch Med, Dept Cardiovasc Med, Aoba Ku, 1-1 Seiryo Machi,Sendai, Miyagi 9808574, Japan Tohoku Univ 1-1 Seiryo Machi Sendai Miyagi Japan 9808574 Japan
Citazione:
Y. Wakayama et al., "Stretch and quick release of rat cardiac trabeculae accelerates Ca2+ wavesand triggered propagated contractions", AM J P-HEAR, 281(5), 2001, pp. H2133-H2142

Abstract

Rapid shortening of active cardiac muscle [quick release (QR)] dissociatesCa2+ from myofilaments. We studied, using muscle stretches and QR, whetherCa2+ dissociation affects triggered propagated contractions (TPCs) and Ca2 waves. The intracellular Ca2+ concentration was measured by a SIT camera in right ventricular trabeculae dissected from rat hearts loaded with fura 2 salt, force was measured by a silicon strain gauge, and sarcomere length was measured by laser diffraction while a servomotor controlled muscle length. TPCs (n=27) were induced at 28 degreesC by stimulus trains (7.5 s at 2.65 +/-0.13 Hz) at an extracellular Ca2+ concentration ([Ca2+](o)) = 2.0 mM or with 10 muM Gd3+ at [Ca2+](o) = 5.2 +/-0.73 mM. QR during twitch relaxation after a 10% stretch for 100-200 ms reduced both the time between the last stimulus and the peak TPC (Peak(TPC)) and the time between the last stimulus and peak Ca2+ wave (Peak(CW)) and increased Peak(TPC) and Peak(CW) (n=13) as well as the propagation velocity (V-prop; n=8). Active force during stretch also increased V-prop (r=0.84, n=12, P<0.01), but Gd3+ had no effect (n=5). These results suggest that Ca2+ dissociation by QR during relaxation accelerates the initiation and propagation of Ca2+ waves.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 15:32:54