[Effect of angiotensin II and its receptor antagonist on electrophysiology and L-type calcium current in guinea cardiac myocytes].
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue
; 18(8): 491-3, 2006 Aug.
Article
en Zh
| MEDLINE
| ID: mdl-16887065
ABSTRACT
OBJECTIVE:
To evaluate the effect of angiotensin II (Ang II) and its receptor antagonist on action potential duration and L-type calcium current density of cardiac myocytes.METHODS:
Single myocyte of the ventricle in guinea was isolated. Action potentials were recorded using a conventional glass microelectrode filled with 3 mol/L KCl solution. Membrane patch clamp whole cell recording technique was used to investigate L-type calcium current maximum in holding potential of -40 mV, length of time 200 ms, command potential 0 mV.RESULTS:
Ang II induced arrhythmia of multiple electrophysiologic mechanisms. Action potential amplitude, 90% of action potential duration (APD90), and resting membrane potential (RMP) were significantly decreased or shortened after being perfused Ang II for 1 minute compared with controls. 30% of action potential duration (APD30), 50% of action potential duration (APD50), effective refractory period (ERP) were also shortened significantly after perfused Ang II for 3 minutes compared with controls. Ang II increased the L-type calcium maximum current density after a perfusion of 5 minutes, but losartan perfusion for 1 minute decreased the L-type calcium maximum current density, and it further decreased after perfusion for 3 minutes. However, the current voltage relationship curve was unchanged.CONCLUSION:
Ang II could decrease amplitude of monophasic action potential, rest membrane potential, shorten duration of monophasic action potential and effective refractory period, increase maximum current density of voltage dependent L-type calcium, and possess the effect of inducing arrhythmia. Losartan decreased maximum current density of voltage dependent L-type calcium.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Angiotensina II
/
Losartán
/
Canales de Calcio Tipo L
/
Miocitos Cardíacos
Límite:
Animals
Idioma:
Zh
Revista:
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue
Asunto de la revista:
MEDICINA DE EMERGENCIA
/
TERAPIA INTENSIVA
Año:
2006
Tipo del documento:
Article
País de afiliación:
China