Confirmation of heterocellular coupling between CM and CF. (A–C) Cocultured cells immunostained with Cx43 (red), FSP-1 (green), and DAPI (blue) with no Gap26 treatment (A) and with 15 μM (B) and 30 μM Gap26 (C). (D–F) Cocultured cells immunostained with Cx43 (red), troponin I (TRP I, green), and DAPI (blue) with no Gap26 treatment (D) and with 15 μM (E) and 30 μM Gap26 (F). Scale bars in (A)–(F) are of the same size and correspond to 50 μM. (G) Average signal intensity of Cx43 expression in cultures with no Gap26 treatment and with 15 μM (B) and 30 μM Gap26.