Electrophysiology and molecular pharmacology of muscle channelopathies.

As voltage-gated ion channels are essential for membrane excitation, it is not surprising that mutations in the respective channel genes cause diseases characterised by altered cell excitability. Skeletal muscle was the first tIssue in which such diseases, namely the myotonias and periodic paralyses, were recognised as ion channelopathies. The detection of the functional defect that is brought about by the disease-causing mutation is essential for the understanding of the pathology. Much progress on the road to this aim was achieved by the combination of molecular biology and electrophysiological patch clamp techniques. The functional expression of the mutations in expression systems allows to study the functional alterations of mutant channels and to develop new strategies for the therapy of ion channelopathies, e.g. by designing drugs that specifically suppress the effects of malfunctioning channels.