Negative inotropic response to cerium in ventricular papillary muscle is mediated by reactive oxygen species.
This study was performed with the objective of assessing the mechanical response of the myocardium to different levels of cerium and delineation of the mechanism underlying the mediation of the functional changes. Rat ventricular papillary muscle was used as the experimental model. Isolated papillary muscles were exposed to different concentrations of CeCl3 and the force of contraction was measured using a force transducer. Experiments have revealed that the negative inotropic response to CeCl3 was proportional to its concentration. The inotropic changes were found to be completely reversible at concentrations < or =5 microM, and partially reversible at higher concentrations. Neutralization of cerium-induced inotropic changes by the superoxide anion scavenger superoxide dismutase (SOD) at concentrations < or =5 microM indicates that the mechanical changes are mediated by reactive oxygen species. At higher concentrations of Ce3+, SOD partially reversed the contractile changes. The beneficial effect of SOD was seen only if the muscles were pretreated with the scavenger prior to the addition of cerium chloride.
Manju
L
L
Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, 695 011, India.
Remani
K
K
Nair
R Renuka
RR
D000818:Animals; D002563:Cerium / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
D017382:Reactive Oxygen Species; D002563:Cerium; D013482:Superoxide Dismutase; C026690:cerous chloride