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Background: Potassium ion (K(+)) plays an essential role in maintaining the electrical potential across the plasma membrane of cells. An abnormal serum K(+) level is associated with increased risk of ventricular arrhythmia and sudden cardiac death (SCD) and these patients are generally prescribed with furosemide and potassium chloride (KCl). We explored the association between the use of these drugs and the risk of SCD by analyzing biochemical parameters and proteomic changes., Materials and Methods: The rats were administered with furosemide and KCl and their effect was analyzed by studying cardiac and oxidative markers, electrolyte content and histopathology. Two-dimensional gel electrophoresis (2-DE) and electrospray ionization-mass spectrometry were performed to investigate the LV proteomic changes., Results: Furosemide and KCl treatments showed significant effect on physiological and biochemical parameters, and LV histopathology of experimental rats. Proteomic analysis indicated 17 differentially expressed proteins. Among them, eight protein spots were identified using peptide mass fingerprinting. In furosemide-treated group, four proteins were upregulated and two proteins were downregulated when compared to 2-DE proteomic profile of control. While in KCl-treated rats, seven proteins were found downregulated., Conclusion: [corrected] The present study revealed the differential expression of proteins by furosemide and KCl treatment. Thus, the results suggest that the use of these drugs leads to proteomic alteration, which involve in cardiac conductivity that might increase the risk of SCD.

Hyperglycemia is independently related with excessive morbidity and mortality in cardiovascular disorders. L-Arginine-nitric oxide (NO) pathway and the involvement of NO in modulating nuclear factor-E2-related factor-2 (Nrf2) signaling were well established. In the present study we investigated, whether L-arginine supplementation would improve the myocardial antioxidant defense under hyperglycemia through activation of Nrf2 signaling. Diabetes was induced by alloxan monohydrate (90 mg kg(-1) body weight) in rats. Both non-diabetic and diabetic group of rats were divided into three subgroups and they were administered either with L-arginine (2.25%) or L-NAME (0.01%) in drinking water for 12 days. Results showed that L-arginine treatment reduced the metabolic disturbances in diabetic rats. Antioxidant enzymes and glutathione levels were found to be increased in heart left ventricles, thereby reduction of lipid peroxidation by L-arginine treatment. Heart histopathological analysis further validates the reversal of typical diabetic characteristics consisting of alterations in myofibers and myofibrillary degeneration. qRT-PCR studies revealed that L-arginine treatment upregulated the transcription of Akt and downregulated NF-κB. Notably, transcription of eNOS and Nrf2 target genes was also upregulated, which were accompanied by enhanced expression of Nrf2 in left ventricular tissue from diabetic and control rats. Under these findings, we suggest that targeting of eNOS and Nrf2 signaling by L-arginine supplementation could be used as a potential treatment method to alleviate the late diabetic complications., (Copyright © 2012 Elsevier Inc. All rights reserved.)