Effects of age and gene dose on skeletal muscle sodium channel gating in mice deficient in myotonic dystrophy protein kinase.

Abstract

Myotonic muscular dystrophy (DM) is characterized by abnormal skeletal muscle Na channel gating and reduced levels of myotonic dystrophy protein kinase (DMPK). Electrophysiological measurements show that mice deficient in Dmpk have reduced Na currents in muscle. We now find that the Na channel expression level is normal in mouse muscle partially or completely deficient in Dmpk. Reduced current amplitudes are not changed by age or gene dose, and the reduction is not due to changes in macroscopic or microscopic gating kinetics. The mechanism of abnormal membrane excitability in DM may in part be silencing of muscle Na channels due to Dmpk deficiency.

• Authors: Sita Reddy, Dilaawar J Mistry, Qing Cai Wang, Lisa M Geddis, Howard C Kutchai, J Randall Moorman, J Paul Mounsey
• Journal: Muscle & nerve (Muscle Nerve) Vol. 25 Issue 6 Pg. 850-7 (Jun 2002) ISSN: 0148-639X [Print] United States
• PMID: 12115974 (Publication Type: Journal Article)
• Copyright: Copyright 2002 Wiley Periodicals, Inc.

Chemical References

• DMPK protein, mouse
• Sodium Channels
• Saxitoxin
• Myotonin-Protein Kinase
• Protein Serine-Threonine Kinases

Topics

• Aging (metabolism)
• Animals
• Cell Separation
• Disease Models, Animal
• Gene Dosage
• In Vitro Techniques
• Ion Channel Gating (drug effects, genetics)
• Kinetics
• Membrane Potentials (drug effects, physiology)
• Mice
• Mice, Inbred Strains
• Mice, Knockout
• Muscle, Skeletal (cytology, metabolism)
• Myotonic Dystrophy (genetics, metabolism)
• Myotonin-Protein Kinase
• Patch-Clamp Techniques
• Protein Serine-Threonine Kinases (deficiency, genetics)
• Radioligand Assay
• Saxitoxin (pharmacokinetics)
• Sodium Channels (drug effects, metabolism)