Bioelectrical signals generated by ion channels play crucial roles in many 
cellular processes in both excitable and nonexcitable cells. Some ion channels 
are directly implemented in chemical signaling pathways, the others are involved 
in regulation of cytoplasmic or vesicular ion concentrations, pH, cell volume, 
and membrane potentials. Together with ion transporters and gap junction 
complexes, ion channels form steady-state voltage gradients across the cell 
membranes in nonexcitable cells. These membrane potentials are involved in 
regulation of such processes as migration guidance, cell proliferation, and body 
axis patterning during development and regeneration. While the importance of 
membrane potential in stem cell maintenance, proliferation, and differentiation 
is evident, the mechanisms of this bioelectric control of stem cell activity are 
still not well understood, and the role of specific ion channels in these 
processes remains unclear. Here we introduce the flatworm Macrostomum lignano as 
a versatile model organism for addressing these topics. We discuss biological 
and experimental properties of M. lignano, provide an overview of the recently 
developed experimental tools for this animal model, and demonstrate how 
manipulation of membrane potential influences regeneration in M. lignano.