Figure 1. Mesoangioblasts contacting C2C12 myotubes respond to ACh.

A, representative field of a co-culture of mesoangioblasts (GFP-positive, white cells) and C2C12 myotubes, as viewed under transmitted light and epifluorescence simultaneously. Arrowhead points to a binucleated mesoangioblast, arrows to mononucleated cells. The patch pipette is on the right. B, the mesoangioblast marked a is isolated, that marked b contacts a myotube through the process indicated by the arrow. Right panel, cell a does not respond to ACh (10 μm, black line), cell b shows an inward current (downward deflection). Holding potential, −70 mV. C, histogram of membrane resting potential of mesoangioblasts cultured alone or with C2C12 myotubes. Values were obtained with a CsCl-based intracellular solution, immediately after membrane rupture.