KCNQ channel expression in MASMCs. Total RNA prepared from rat MASMCs or adult rat brain (as a positive control) was reverse transcribed and subjected to PCR using primers specific for rat KCNQ1 through KCNQ5. Molecular weight marker (M) is a 100-bp ladder (New England Biolabs, Ipswich, MA); 500 bp is indicated to the left of each panel. Expected sizes of each reaction product are KCNQ1, 453 bp; KCNQ2, 372 bp; KCNQ3, 424 bp; KCNQ4, 359 bp; and KCNQ5, 240 bp.