Apparatus (800) for targeted release of a molecule carried in a circulating reservoir, comprising: at least one electrode (804); and a controller (810) adapted to electrify said electrode (804) with at least one electric field, said electric field operative to have at least one desired effect related to said circulating reservoir with said molecule, wherein said electrode and said electrification are adapted such that at least one of said effects is selectively applied to a particular blood vessel that carries blood through tissue and wherein said at least one effect that is selectively applied comprises a release effect, which releases said molecule from said circulating reservoir that circulates in said blood vessel.