Figure 1.

Expression of genes encoding different Na⁺ channel isoforms Na_vx

RT-PCR analysis of Na_v transcripts in normal and failing human (A) and dog (B) left ventricular tissue samples. A, from left to right: Na_v1.1 isoform obtained in normal heart (NH), in explanted heart from patients with ischaemic (IHF), and non-ischaemic (NIHF) heart failure, respectively. The expected 491 bp band was not detected in NH and NIHF, Na_v1.2 isoform (417 bp), Na_v1.3 isoform (189 bp), Na_v1.6 isoform. A specific band of 155 bp is missing in IHF; a non-specific smaller band is present instead. Na_v2.1 isoform (586 bp). B, the same Na⁺ channel isoforms as shown in A were obtained in dog normal (NH) and failing (HF) hearts. Last gel lane on right represents standard bp marker. C, summary data with statistics for Na_v isoforms expressed in human heart. RT-PCR gels were analysed in 5–7 tissue samples from left ventricles, D, summary data with statistics for Na_v isoforms expressed in dog heart. RT-PCR gels were analysed in 5 samples of ventricular cardiac myocytes from left ventricles of normal dog hearts and failing dog hearts, respectively. *P < 0.05, ANOVA, data are mean ± SEM for both C and D.