Role of reactive oxygen species in acetylcholine-induced preconditioning in cardiomyocytes

Zhenhai Yao*, Jiankun Tong, Xiaohui Tan, Changqing Li, Zuohui Shao, Woo Chan Kim, Terry L. Vanden Hoek, Lance B. Becker, C. Alvin Head, Paul T. Schumacker

*Corresponding author for this work

Research output: Contribution to journalArticle

113 Scopus citations

Abstract

We examined the ability of ACh to mimic ischemic preconditioning in cardiomyocytes and the role of ATP-sensitive potassium (K(ATP)) channels and mitochondrial reactive oxygen species (ROS) in mediating this effect. Chick embryonic ventricular myocytes were studied in a flow-through chamber while flow rate, pH, PO2, and PCO2 were controlled. Cell viability was quantified with propidium iodide (5 μM), and production of ROS was measured using 2',7'-dichlorofluorescin diacetate. Data were expressed as means ± SE. Preconditioning with 10 min of ischemia followed by 10 min of reoxygenation or 10 min of ACh (1 mM) followed by a drug-free period before 1 h of ischemia and 3 h of reoxygenation reduced cell death to the same extent [preconditioning 19 ± 2% (n = 6, P < 0.05) ACh 21 ± 5% (n = 6, P < 0.05) vs controls 42 ± 5% (n = 9)]. Like preconditioning, ACh increased ROS production threefold before ischemia [0.60 ± 0.16 (n = 7, P < 0.05) vs. controls, 0.16 ± 0.03 (n = 6); arbitrary units]. Protection and increased ROS production during ACh preconditioning were abolished with 5- hydroxydecanoate (5-HD, 100 μM), a selective mitochondrial K(ATP) channel antagonist, and the thiol reductant 2-mercaptopropionyl glycine (2-MPG, 1 mM), an antioxidant [cell death: 5-HD+ACh 37 ± 7% (n = 5), 2-MPG+ACh 47 ± 6% (n = 6); ROS signals: 5-HD+ACh 0.09 ± 0.03 (n = 5), 2-MPG+ACh 0.01 ± 0.04 (n = 4)]. In addition, ACh-induced ROS signaling was blocked by the mitochondrial site III electron transport inhibitor myxothiazol (0.02 ± 0.07, n = 5). These results demonstrate that activation of mitochondrial K(ATP) channels and increased ROS production from mitochondria are important intracellular signals that participate in ACh-induced preconditioning in cardiomyocytes.

Original languageEnglish (US)
Pages (from-to)H2504-H2509
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume277
Issue number6 46-6
StatePublished - Dec 1 1999

Keywords

  • Adenosine 5'-triphosphate-dependent potassium channels
  • Mitochondria
  • Reactive oxygen species
  • Signal transduction

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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  • Cite this

    Yao, Z., Tong, J., Tan, X., Li, C., Shao, Z., Kim, W. C., Vanden Hoek, T. L., Becker, L. B., Head, C. A., & Schumacker, P. T. (1999). Role of reactive oxygen species in acetylcholine-induced preconditioning in cardiomyocytes. American Journal of Physiology - Heart and Circulatory Physiology, 277(6 46-6), H2504-H2509.