Fig. 1.

Immunostaining of sodium channel α subunits Na_v1.1, 1.3, 1.6, 1.2, 1.4 and 1.5 in human atrium. Tissue section double-labelled with anti-Na_v1.1 (A) and α actinin (B) demonstrating punctate surface labelling of Na_v1.1 channels that does not overlap with the z-lines when the images are merged (C). Human atrial tissue labelled with anti-Na_v1.3 (D) or anti-Na_v1.6 (E) illustrating punctate surface staining of these channels, similar to anti-Na_v1.1. (F) Control section in which the primary antibody was omitted illustrating specificity of staining. Tissue section double labelled with anti-Na_v1.2 (G) and anti-connexin 43 (H) illustrating a high density of Na_v1.2 channels at the intercalated disk region (I, merged) and relatively low density of staining in a banded pattern along the length of the myocyte. (J) Higher magnification of a tissue section double labelled with anti-Na_v1.2 (green) and anti-connexin 43 (red) illustrating the staining of these two proteins at the intercalated disk region. (K) Staining of anti-Na_v1.4 on atrial tissue illustrating staining in a banded pattern along the myocyte. (L) Atrial tissue double-labelled with anti-Na_v1.5 (green) and anti-connexin 43 (red). (M, N) High magnification image of tissue double-labelled with anti-Na_v1.5 (M) and α-actinin (N) showing that the banded pattern of Na_v1.5 staining is in register with the staining of α-actinin at the z-lines (O). Scale bars = 5 μm.