Year: 2018
Type: article
Abstract: In adult left ventricular mouse myocytes, exposure to sodium cyanide (NaCN) in the presence of glucose dose-dependently reduced contraction amplitude, with ~80% of maximal inhibitory effect attained at 100 µM. NaCN (100 µM) exposure for 10 min significantly decreased contraction and intracellular Ca2+concentration ([Ca2+]i) transient amplitudes, systolic but not diastolic [Ca2+]i, and maximal L-type Ca2+current ( ICa) amplitude, indicating acute alteration of [Ca2+]ihomeostasis largely accounted for the observed excitation-contraction abnormalities. In addition, NaCN depolarized resting membrane potential ( Em), reduced action potential (AP) amplitude, prolonged AP duration at 50% (APD50) and 90% repolarization (APD90), and suppressed depolarization-activated K+currents but had no effect on Na+-Ca2+exchange current ( INaCa). NaCN did not affect cellular adenosine triphosphate levels but depolarized mitochondrial membrane potential (ΔΨm) and increased superoxide (O2·−) levels. Methylene blue (MB; 20 µg/ml) added 3 min after NaCN restored contraction and [Ca2+]itransient amplitudes, systolic [Ca2+]i, Em, AP amplitude, APD50, APD90, ICa, depolarization-activated K+currents, ΔΨm, and O2·−levels toward normal. We conclude that MB reversed NaCN-induced cardiotoxicity by preserving intracellular Ca2+homeostasis and excitation-contraction coupling ( ICa), minimizing risks of arrhythmias ( Em, AP configuration, and depolarization-activated K+currents), and reducing O2·−levels. NEW & NOTEWORTHY Cyanide poisoning due to industrial exposure, smoke inhalation, and bioterrorism manifests as cardiogenic shock and requires rapidly effective antidote. In the early stage of cyanide exposure, adenosine triphosphate levels are normal but myocyte contractility is reduced, largely due to alterations in Ca2+homeostasis because of changes in oxidation-reduction environment of ion channels. Methylene blue, a drug approved by the U.S. Food and Drug Administration, ameliorates cyanide toxicity by normalizing oxidation-reduction state and Ca2+channel function.
Source: Journal of Applied Physiology
Institutions: Temple University, Pennsylvania State University
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Awards: G1157665003, G1980822575, G2265823535, G240415731, Effects of acute administration of the Phenothiazinium Chromophore Methylene blue during life threatening cyanide intoxication, TRPM2 and Oxidative Cardiac Injury, G3767025027, G3981397070, Involvement of BAG3 in HIV-1 induced cardiomyopathy, G4726664506, G4848328518, Molecular mechanism of Ca2+-induced mitochondrial shape transition in metazoans, G6529075534, G6671857107
OpenAlex ID: W2785404304