Automated analysis equipment and assay method for detecting cell surface protein function using same

An automated drug screening assay method for identifying compounds that modulate the activity of ion channels and/or receptors of a cell, comprising:

• (a) introducing a divided culture vessel that has an array of individual compartments into an automated assay apparatus, wherein:
• the apparatus delivers reagent solution to one or more of the compartments and has detection means to measure transient changes in an optical attribute in the compartments;
• at least two of the compartments contain viable cells that comprise either or both the ion channel and receptor;
• at least one, and up to one fewer than all of the cell-containing compartments also comprises one or more test compound(s) that is (are) being screened for the ability to modulate the activity of the ion channel or receptor;
• the ion channel or receptor, when activated, directly or indirectly contributes to a detectable change in the cytoplasmic level of a predetermined ion in the cells;
• and
• the cytoplasm of the cells contains an amount of an ion-sensitive fluorescent indicator sufficient to detect a change in the concentration of the predetermined ion;
• (b) automatically delivering to a cell-containing compartment, an aliquot of a solution comprising an amount of a known ion channel- or receptor-activating compound that activates the ion channel or receptor, whereby, the change in concentration of the predetermined ion commences;
• (c) within a time period before any induced ion concentration change would be at a maximum, automatically detecting and measuring for a predetermined amount of time in the cell-containing compartment to which an aliquot of solution has been added ion flux by measuring fluorescence emitted by the ion-sensitive indicator in response to an excitation wavelength, whereby compounds that modulate the activity of ion channels and/or receptors of a cell are identified.