The expression of ion channel mRNAs in skeletal muscles from patients withmyotonic muscular dystrophy

We investigated gene expression patterns of ion channels including the apam in-sensitive small-conductance Ca2+-activated K+ (SK3) channel, the adult i soform of the skeletal muscle Na+ channel (SkM1), the fetal isoform of skel etal muscle Na+ channel (H1), and the Cl- channel (CIC-1) by using the semi quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for m uscle samples from patients with adult onset myotonic dystrophy (DM), amyot rophic lateral sclerosis, and polymyositis. Patients with DM showed a signi ficant increase in SK3 mRNA but not in mRNAs for other ion channels. The in creased expression of SK3 gene in DM did not correlate with HI, the marker of muscle denervation, or the percentage of type 2C fiber, the marker of mu scle regeneration. (C) 2000 Elsevier Science Ireland Ltd. All rights reserv ed.