Patent ID: 7425410

Claim:
A method for diagnosing a bipolar disorder in a human patient, comprising: (a) obtaining a ratio of (i) the mean membrane potential of cells of a test human patient incubated in vitro in the presence of a compound that alters Na + K + ATPase activity, but in the absence of K + , to (ii) the mean membrane potential of cells of the test human patient incubated in vitro in the absence of the compound that alters Na + K + ATPase activity, but in the presence of K + ; and one or both of the following steps (b) and (c): (b) comparing the ratio obtained in (a) to a control ratio, wherein the control ratio is the ratio of (iii) the mean membrane potential of corresponding control cells of one or more humans known to not have said bipolar disorder incubated in vitro in the presence of a compound that alters Na + K + ATPase activity, but in the absence of K + , to (iv) the mean membrane potential of corresponding control cells of one or more humans known to not have said bipolar disorder incubated in vitro in the absence of the compound that alters Na + K + ATPase activity, but in the presence of K + , wherein when the ratio obtained in (a) is significantly lower than the control ratio obtained in (b), said test human patient is diagnosed as having said bipolar disorder; (c) comparing the ratio obtained in (a) to a bipolar control ratio, wherein the bipolar control ratio is the ratio of (v) the mean membrane potential of corresponding bipolar control cells of one or more humans known to have said bipolar disorder incubated in vitro in the presence of a compound that alters Na + K + ATPase activity, but in the absence of K + , to (vi) the mean membrane potential of corresponding bipolar control cells of one or more humans known to have said bipolar disorder incubated in vitro in the absence of the compound that alters Na + K + ATPase activity, but in the presence of K + , wherein when the ratio obtained in (a) is not significantly different than the bipolar control ratio obtained in (c), said test human patient is diagnosed as having bipolar disorder wherein each mean membrane potential is determined by incubating the cells in vitro in buffer comprising a potential-sensitive dye, resuspending the cells in potential-sensitive dye free-buffer, and measuring cell fluorescence.