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Effects of apocynin on ISO-induced delayed afterdepolarizations in rat atrial myocytes and the underlying mechanisms.
Zhang, Nan; Dan, Qing; Dong, Ying; Liu, Yan; Zhuang, Wenjuan; Xie, Zhonghui; Zhao, Qianqian; Lin, Kun; Li, Yang.
Afiliación
  • Zhang N; Medical School of Chinese PLA, Beijing, 100853, China; Department of Cardiology, the Sixth Medical Center, Chinese PLA General Hospital, Beijing, 100048, China.
  • Dan Q; Department of Cardiology, the First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China.
  • Dong Y; Department of Cardiology, the First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China.
  • Liu Y; Department of Health Care, Northern Medical Branch of PLA General Hospital, Beijing, 100091, China.
  • Zhuang W; Department of Internal Medicine, Beijing Changping District Shahe Hospital, Beijing, 102206, China.
  • Xie Z; Medical School of Chinese PLA, Beijing, 100853, China; Department of Cardiology, the Sixth Medical Center, Chinese PLA General Hospital, Beijing, 100048, China.
  • Zhao Q; Medical School of Chinese PLA, Beijing, 100853, China; Department of Cardiology, the Sixth Medical Center, Chinese PLA General Hospital, Beijing, 100048, China.
  • Lin K; Department of Outpatient, the First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China.
  • Li Y; Department of Cardiology, the Sixth Medical Center, Chinese PLA General Hospital, Beijing, 100048, China. Electronic address: liyangbsh@163.com.
Biochem Biophys Res Commun ; 638: 36-42, 2023 01 01.
Article en En | MEDLINE | ID: mdl-36436340
We aimed to investigate the effect of apocynin (APO) on delayed afterdepolarizations (DADs) in rat atrial myocytes and the underlying mechanisms. Rat atrial myocytes were isolated by a Langendorff perfusion apparatus. DADs were induced by isoproterenol (ISO). Action potentials (APs) and ion currents were recorded by the whole-cell clamp technique. The fluorescent indicator fluo-4 was used to visualize intracellular Ca2+ transients, and western blotting was used to measure the expression of related proteins. The incidence of DADs in rat atrial myocytes increased significantly after ISO treatment, leading to an increased incidence of triggered activity (TA). The incidence of ISO-induced DADs and TA were reduced by 100.0 µM APO from 48.89% to 25.56% and 17.78% to 5.56%, respectively. In the range of 3.0 µM-300.0 µM, the effect of APO was concentration dependent, with a half maximal inhibitory concentration (IC50) of 120.1 µM and a Hill coefficient of 1.063. APO reversed the increase in transient inward current (Iti) and Na+/Ca2+-exchange current (INCX) densities induced by ISO in atrial myocytes. The frequency of spontaneous Ca2+ transients in atrial myocytes was reduced by 100.0 µM APO. Compared with ISO, APO downregulated the expression of NOX2 and increased the phosphorylation of PLNSer16 and the sarcoplasmic reticulum Ca2+-ATPase-2a (SERCA2a) level; however, it had little effect on ryanodine-receptor channel type-2 (RyR2). These findings showed that APO may block Iti and INCX and reduce intracellular Ca2+ levels in rat atrial myocytes, thus reducing the incidence of ISO-induced DADs and TA.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Fibrilación Atrial Límite: Animals Idioma: En Revista: Biochem Biophys Res Commun Año: 2023 Tipo del documento: Article País de afiliación: China Pais de publicación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Fibrilación Atrial Límite: Animals Idioma: En Revista: Biochem Biophys Res Commun Año: 2023 Tipo del documento: Article País de afiliación: China Pais de publicación: Estados Unidos