Patent ID: 7754440

Claim:
A method for identifying a selective blocker of a persistent Na + channel whereby the method comprises the steps of: a) providing a test sample 1 comprising i) a physiological solution; ii) a voltage-sensitive fluorescence dye; and iii) a cell having a K + channel and a persistent Na + channel wherein a resting membrane potential of the cell is between −50 mV to −20 mV; b) detecting fluorescence emitted by the voltage-sensitive dye in test sample 1; c) adding a potential Na + channel blocker to test sample 1; d) detecting fluorescence emitted by the voltage-sensitive dye in test sample 1; e) determining a relative emitted fluorescence 1 by comparing the emitted fluorescence from step (b) with the emitted fluorescence from step (d); f) providing a test sample 2 comprising i) a physiological solution; ii) a voltage-sensitive fluorescence dye; iii) a cell having a K + channel and a transient Na + channel; and iv) a potential Na + channel blocker g) depolarizing the membrane of the cell in test sample 2; h) detecting the fluorescence emitted by the voltage-sensitive dye in test sample 2; i) providing a control sample 2 comprising i) a physiological solution; ii) a voltage-sensitive fluorescence dye; and iii) a cell having a K + channel and a transient Na + channel; j) depolarizing the membrane of the cell in control sample 2; k) detecting the fluorescence emitted by the voltage-sensitive dye in control sample 2; l) determining a relative emitted fluorescence 2 by comparing the emitted fluorescence from step (h) relative to an emitted fluorescence from step (k); m) comparing the relative emitted fluorescence in step (e) with the relative emitted fluorescence in step (l); wherein a decrease in emitted fluorescence from step (e) relative to the emitted fluorescence in step (l) is indicative of the presence of a selective persistent Na + channel blocker in the test sample.