Patent ID: 7270949

Claim:
A method to detect the activation of T-type calcium ion channels, which method comprises treating cells that express at least the α 1 subunit of a T-type calcium ion channel with sufficient potassium ion to activate said T-type channel, and measuring the fluorescence emitted by such cells, wherein the cells have been modified to contain a fluorophore having an intensity of emission that changes in the presence of calcium ion, and wherein said cells have been treated, prior to treating with potassium ion to activate said T-type channel, with a monovalent cation-selective pore-forming substance that permits the influx and efflux of singly charged cations so as to create a cation-selective pore in the presence of a solution comprising at least one osmolality balancing component that does not permeate said pore, wherein said solution is an isotonic solution prepared by substituting said at least one osmolality balancing component for sodium ions, wherein enhancement of the intensity of fluorescence emission indicates the activation of said T-type calcium ion channels.