The invention provides an agent that reduces the expression of G\u03b112 or G\u03b113 polypeptide, as well as an agent that enhances G protein G\u03b112 or G\u03b113 expression andor activity. One or more of a first conductor or set of conductors is disposed externally andor internally on or within the structure and an array of elongate electrically conductive elements are disposed radially outwardly within the volume. The first common layer may include a first doping layer and a second doping layer disposed on the first doping layer.