Molecular basis for decreased muscle chloride conductance in the myotonic goat.
AUTOR(ES)
Beck, C L
RESUMO
Certain forms of myotonia, a condition characterized by delayed relaxation of muscle secondary to sarcolemmal hyperexcitability, are caused by diminished chloride conductance in the muscle cell membrane. We have investigated the molecular basis for decreased muscle chloride conductance in the myotonic goat, an historically important animal model for the elucidation of the role of chloride in muscle excitation. A single nucleotide change causing the substitution of proline for a conserved alanine residue in the carboxyl terminus of the goat muscle chloride channel (gCIC-1) was discovered. Heterologous expression of the mutation demonstrated a substantial (+47 mV) shift in the midpoint of steady-state activation of the channel, resulting in a diminished channel open probability at voltages near the resting membrane potential of skeletal muscle. These results provide a molecular basis for the decreased chloride conductance in myotonic muscle.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=38315Documentos Relacionados
- Molecular Basis for Impaired Muscle Differentiation in Myotonic Dystrophy
- Effects of specific carotid body and brain hypoxia on respiratory muscle control in the awake goat.
- Decreased insulin sensitivity of forearm muscle in myotonic dystrophy.
- On the molecular basis for chemomechanical energy transduction in muscle.
- Prepartum milking and the onset of secretion of milk fat in the goat.