A method of modifying the electrophysiological function of an excitable
tissue region of an individual is provided. The method includes the step
of implanting cells into the excitable tissue region. Each implanted cell
is (a) capable of forming gap junctions with at least one cell of the
excitable tissue region; and (b) capable of forming a functional ion
channel or transporter, wherein the functional ion channel or transporter
is capable of modifying the electrophysiological function of the
excitable tissue region.