Ordered Assembly of the Adhesive and Electrochemical Connections within Newly Formed Intercalated Disks in Primary Cultures of Adult Rat Cardiomyocytes
Figure 9
The α subunit of the voltage-gated sodium channel is incorporated significantly later into the newly-formed intercalated disks. ARCs at 5 (a)–(d) and 13 (e)–(g) days post plating were immunolabeled for Nav1.5 (red: (a)–(e) and (g)) and PKP2 (green: a, e, f) or α-actinin (green: (c)). (a, b) At the 5-day timepoint, there is no detectable localization of Nav1.5 even to mature cell adhesion sites (arrowhead). (c, d) Instead, Nav1.5 appears to be more closely associated with assembling myofibrils (arrowhead). Note the linear arrays of Nav1.5 immunolabeling between α-actinin-labeled myofibrils. (e)–(g) By 13 days post plating, the channel has localized to the new intercalated disk, significantly after the other components. Scale bars are 10 m (a)–(d) and 20 m (e)–(g).
