Effects of sphingosine 1-phosphate on excitation–contraction coupling in mammalian skeletal muscle

Bencini, C. et al. (2003) Effects of sphingosine 1-phosphate on excitation–contraction coupling in mammalian skeletal muscle. Journal of Muscle Research and Cell Motility, 24(8), pp. 539-554. (doi: 10.1023/B:JURE.0000009898.02325.58) (PMID:14870969)

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Abstract

Sphingosine 1-phosphate (S1P) activates a subset of plasma membrane receptors of the endothelial differentiation gene family (EdgRs) in many cell types. In C2C12 myoblasts, exogenous S1P elicits Ca2+ transients by activating voltage-independent plasma membrane Ca2+ channels and intracellular Ca2+ -release channels. In this study, we investigated the effects of exogenous S1P on voltage-dependent L-type Ca2+ channels in skeletal muscle fibers from adult mice. To this end, intramembrane charge movements (ICM) and L-type Ca2+ current (I Ca) were measured in single cut fibers using the double Vaseline-gap technique. Our data showed that submicromolar concentrations of S1P (100 nM) caused a ∼10-mV negative shift of the voltage threshold and transition voltages of q γ and q h components of ICM, and of I Ca activation and inactivation. Biochemical studies showed that EdgRs are expressed in skeletal muscles. The involvement of EdgRs in the above S1P effects was tested with suramin, a specific inhibitor of Edg-3Rs. Suramin (200 μM) significantly reduced, by ∼90%, the effects of S1P on ICM and I Ca, suggesting that most of S1P action occurred via Edg-3Rs. Moreover, S1P at concentration above 10 μM elicited intracellular Ca2+ transients in muscle fibers loaded with the fluorescent Ca2+ dye Fluo-3, as detected by confocal laser scanning microscopy.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Vassalli, Dr Massimo
Authors: Bencini, C., Squecco, R., Piperio, C., Formigli, L., Meacci, E., Nosi, D., Tiribilli, B., Vassalli, M., Quercioli, F., Bruni, P., Zecchi Orlandini, S., and Francini, F.
College/School:College of Science and Engineering > School of Engineering > Biomedical Engineering
Journal Name:Journal of Muscle Research and Cell Motility
Publisher:Springer
ISSN:0142-4319
ISSN (Online):1573-2657

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