RGD Reference Report - Mechanism of action of endothelin in rat cardiac muscle: cross-bridge kinetics and myosin light chain phosphorylation. - Rat Genome Database

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Mechanism of action of endothelin in rat cardiac muscle: cross-bridge kinetics and myosin light chain phosphorylation.

Authors: Rossmanith, GH  Hoh, JF  Turnbull, L  Ludowyke, RI 
Citation: Rossmanith GH, etal., J Physiol. 1997 Nov 15;505 ( Pt 1):217-27.
RGD ID: 1600167
Pubmed: PMID:9409484   (View Abstract at PubMed)
PMCID: PMC1160106   (View Article at PubMed Central)

1. The molecular mechanism of inotropic action of endothelin was investigated in rat ventricular muscle by studying its effects on characteristics of isometric twitch, barium-induced steady contracture and the level of incorporation of 32Pi into myosin light chain 2. 2. Exposure of rat papillary muscle to endothelin caused an increase in isometric twitch force but did not alter the twitch-time parameters. 3. Endothelin did not significantly change the maximum contracture tension but did cause an increase in contracture tension at submaximal levels of activation, without changes in the tension-to-stiffness ratio and kinetics of attached cross-bridges. Kinetics of attached cross-bridges were deduced during steady contracture from complex-stiffness values, and in particular from the frequency at which muscle stiffness assumes a minimum value, fmin. Endothelin did not alter fmin. 4. Endothelin caused an increase in the level of incorporation of 32Pi into myosin light chain 2 without a concurrent change in the level of incorporation of 32Pi into troponin I. 5. We conclude that the inotropic action of endothelin is not due to an increase in the kinetics of attached cross-bridges, nor due to a change in the force per unit cross-bridge, but may result from an increased divalent cation sensitivity caused by elevated myosin light chain 2 phosphorylation, resembling post-tetanic potentiation in fast skeletal muscle fibres.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
cardiac muscle contraction  IMP 1600167; 1600167; 1600167; 1600167 RGD 

Cellular Component
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
contractile fiber  IDA 1600167; 1600167; 1600167; 1600167 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Myl1  (myosin, light chain 1)
Myl2  (myosin light chain 2)
Tnnc1  (troponin C1, slow skeletal and cardiac type)
Tnni3  (troponin I3, cardiac type)


Additional Information