Intracellular Ca2+ transients in delta-sarcoglycan knockout mouse skeletal muscle
| Autor: | Alejandro Zentella-Dehesa, Jorge A. Sánchez, Alhondra Solares-Pérez, Ramón Mauricio Coral-Vázquez, Maria C. Garcia |
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| Rok vydání: | 2009 |
| Předmět: |
medicine.medical_specialty
Muscle Fibers Skeletal Biophysics Stimulation Mice Inbred Strains Biology Biochemistry Calcium in biology Mice Reference Values Internal medicine Sarcoglycans medicine Myocyte Animals Humans Muscular dystrophy Muscle Skeletal Molecular Biology Calcium metabolism Mice Knockout Voltage-dependent calcium channel Skeletal muscle Muscular Dystrophy Animal medicine.disease Electric Stimulation Hindlimb Endocrinology medicine.anatomical_structure Calcium ITGA7 Signal Transduction |
| Zdroj: | Biochimica et biophysica acta. 1800(3) |
| ISSN: | 0006-3002 |
| Popis: | BACKGROUND delta-Sarcoglycan (delta-SG) knockout (KO) mice develop skeletal muscle histopathological alterations similar to those in humans with limb muscular dystrophy. Membrane fragility and increased Ca(2+) permeability have been linked to muscle degeneration. However, little is known about the mechanisms by which genetic defects lead to disease. METHODS Isolated skeletal muscle fibers of wild-type and delta-SG KO mice were used to investigate whether the absence of delta-SG alters the increase in intracellular Ca(2+) during single twitches and tetani or during repeated stimulation. Immunolabeling, electrical field stimulation and Ca(2+) transient recording techniques with fluorescent indicators were used. RESULTS Ca(2+) transients during single twitches and tetani generated by muscle fibers of delta-SG KO mice are similar to those of wild-type mice, but their amplitude is greatly decreased during protracted stimulation in KO compared to wild-type fibers. This impairment is independent of extracellular Ca(2+) and is mimicked in wild-type fibers by blocking store-operated calcium channels with 2-aminoethoxydiphenyl borate (2-APB). Also, immunolabeling indicates the localization of a delta-SG isoform in the sarcoplasmic reticulum of the isolated skeletal muscle fibers of wild-type animals, which may be related to the functional differences between wild-type and KO muscles. CONCLUSIONS delta-SG has a role in calcium homeostasis in skeletal muscle fibers. GENERAL SIGNIFICANCE These results support a possible role of delta-SG on calcium homeostasis. The alterations caused by the absence of delta-SG may be related to the pathogenesis of muscular dystrophy. |
| Databáze: | OpenAIRE |
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