Fig 3. A schematic diagram showing the attenuation of the AP foot convexity and after depolarization amplitude based on distance from the varicosity.

The smooth muscle cells, connected via the gap junctions allow the unattenuated active transmission of APs (shown in black trace). The underlying sEJP (shown in blue trace) is passive signal and is attenuated with distance. The reduced amplitude of the underlying sEJP over distance is visible in the foot and the ADP amplitude (indicated by the arrows) of the observed sAP. At a sufficiently large distance, the underlying sEJP disappears and the observed AP attains the shape of the native AP.