Stereoselective binding of levosimendan to cardiac troponin C causes Ca2+-sensitization
Author
Summary, in English
The effects of the Ca2+ sensitizer levosimendan and that of its stereoisomer dextrosimendan on the cardiac contractile apparatus were studied using skinned fibers obtained from guinea pig hearts. Levosimendan was found to be more effective than dextrosimendan in this model. The respective concentrations of levosimendan and dextrosimendan at EC50 were 0.3 and 3 muM. In order to explain the difference in efficacy as Ca2+ sensitizers, the binding of the two stereoisomers on cardiac troponin C was studied by nuclear magnetic resonance in the absence and presence of two peptides of cardiac troponin I. The two stereoisomers interacted with both domains of cardiac troponin C in the absence of cardiac troponin I. In the presence of cardiac troponin I-(32-79) and cardiac troponin I-(128-180), the binding of both levosimendan and dextrosimendan to the C-terminal domain of cardiac troponin C was blocked and only the binding to the N-terminal domain was observable. Differences in the overall binding behavior of the two isomers to cardiac troponin C were highlighted in order to discuss their structure to activity relation. Our data are consistent with the notion that the action of levosimendan as a Ca2+ sensitizer and positive inotrope relates to its stereoselective binding to Ca2+-saturated cardiac troponin C. (C) 2003 Elsevier B.V. All rights reserved.
Department/s
Publishing year
2004
Language
English
Pages
1-8
Publication/Series
European Journal of Pharmacology
Volume
486
Issue
1
Document type
Journal article
Publisher
Elsevier
Topic
- Pharmacology and Toxicology
Keywords
- Cardiac troponin C
- Levosimendan
- NMR (nuclear magnetic resonance)
- Drug interaction
Status
Published
ISBN/ISSN/Other
- ISSN: 1879-0712