Methods of reducing the excitability of an excitable cell by transforming an excitable cell with a nucleic acid construct encoding an open rectifier K.sup.+ channel (dORK) (SEQ ID NO:2) or a modified open rectifier K.sup.+ channel (dORK.DELTA.) (SEQ ID NO:4), and expressing the open rectifier K.sup.+ channel in the excitable cell, wherein the excitability of the transformed cell is reduced. Also featured are transgenic animals expressing dORK or dORK.DELTA..