21 June 2011
Regulation of the instantaneous inward rectifier and the delayed outward rectifier potassium channels by Captopril and Angiotensin II via the Phosphoinositide-3 kinase pathway in volume-overload-induced hypertrophied cardiac myocytes
Zikiar V. AlvinABCDEF, Graham G. LaurenceABCE, Bernell R. ColemanDE, Aiqiu ZhaoABCD, Majd Hajj-MoussaACDE, Georges E. HaddadABCDEFGDOI: 10.12659/MSM.881843
Med Sci Monit 2011; 17(7): BR165-172
Abstract
Background: Early development of cardiac hypertrophy may be beneficial but sustained hypertrophic activation leads to myocardial dysfunction. Regulation of the repolarizing currents can be modulated by the activation of humoral factors, such as angiotensin II (ANG II) through protein kinases. The aim of this work is to assess the regulation of IK and IK1 by ANG II through the PI3-K pathway in hypertrophied ventricular myocytes.
Material/Methods: Cardiac eccentric hypertrophy was induced through volume-overload in adult male rats by aorto-caval shunt (3 weeks). After one week half of the rats were given captopril (2 weeks; 0.5 g/l/day) and the other half served as control. The voltage-clamp and western blot techniques were used to measure the delayed outward rectifier potassium current (IK) and the instantaneous inward rectifier potassium current (IK1) and Akt activity, respectively.
Results: Hypertrophied cardiomyocytes showed reduction in IK and IK1. Treatment with captopril alleviated this difference seen between sham and shunt cardiomyocytes. Acute administration of ANG II (10–6M) to cardiocytes treated with captopril reduced IK and IK1 in shunts, but not in sham. Captopril treatment reversed ANG II effects on IK and IK1 in a PI3-K-independent manner. However in the absence of angiotensin converting enzyme inhibition, ANG II increased both IK and IK1 in a PI3-K-dependent manner in hypertrophied cardiomyocytes.
Conclusions: Thus, captopril treatment reveals a negative effect of ANG II on IK and IK1, which is PI3-K independent, whereas in the absence of angiotensin converting enzyme inhibition IK and IK1 regulation is dependent upon PI3-K.
Keywords: Patch-Clamp Techniques, Myocytes, Cardiac - physiology, Delayed Rectifier Potassium Channels - metabolism, Cardiomegaly - physiopathology, Captopril - pharmacology, Blotting, Western, Angiotensin II - pharmacology, Phosphatidylinositol 3-Kinases - metabolism, Potassium Channels, Inwardly Rectifying - metabolism
Editorial
01 March 2024 : Editorial
Editorial: First Regulatory Approvals for CRISPR-Cas9 Therapeutic Gene Editing for Sickle Cell Disease and Transfusion-Dependent β-ThalassemiaDOI: 10.12659/MSM.944204
Med Sci Monit 2024; 30:e944204
In Press
21 Feb 2024 : Clinical Research
Potential Value of HSP90α in Prognosis of Triple-Negative Breast CancerMed Sci Monit In Press; DOI: 10.12659/MSM.943049
22 Feb 2024 : Review article
Differentiation of Native Vertebral Osteomyelitis: A Comprehensive Review of Imaging Techniques and Future ...Med Sci Monit In Press; DOI: 10.12659/MSM.943168
23 Feb 2024 : Clinical Research
A Study of 60 Patients with Low Back Pain to Compare Outcomes Following Magnetotherapy, Ultrasound, Laser, ...Med Sci Monit In Press; DOI: 10.12659/MSM.943732
26 Feb 2024 : Clinical Research
Predictive Value of Combined HbA1c and Neutrophil-to-Lymphocyte Ratio for Diabetic Peripheral Neuropathy in...Med Sci Monit In Press; DOI: 10.12659/MSM.942509
Most Viewed Current Articles
17 Jan 2024 : Review article
Vaccination Guidelines for Pregnant Women: Addressing COVID-19 and the Omicron VariantDOI :10.12659/MSM.942799
Med Sci Monit 2024; 30:e942799
16 May 2023 : Clinical Research
Electrophysiological Testing for an Auditory Processing Disorder and Reading Performance in 54 School Stude...DOI :10.12659/MSM.940387
Med Sci Monit 2023; 29:e940387
14 Dec 2022 : Clinical Research
Prevalence and Variability of Allergen-Specific Immunoglobulin E in Patients with Elevated Tryptase LevelsDOI :10.12659/MSM.937990
Med Sci Monit 2022; 28:e937990
01 Jan 2022 : Editorial
Editorial: Current Status of Oral Antiviral Drug Treatments for SARS-CoV-2 Infection in Non-Hospitalized Pa...DOI :10.12659/MSM.935952
Med Sci Monit 2022; 28:e935952