Methods for identifying modulators of membrane potentials in bipolar disorder and attention deficit hyperactivity disorder

Abstract

The present invention provides methods to modulate key elements along the DAG signaling pathway as well as a diagnostic assay, device and methods of using the same to diagnose bipolar disorder (BD) and attention deficit hyperactivity disorder (ADHD). Methods to identify diagnostic markers and drug targets for BD and ADHD. Methods of identifying effective compounds responsible for membrane potentials and excitabilities influencing bipolar disorder (BD) and attention deficit hyperactivity disorder (ADHD). Methods of identifying an effective compound that modulates the activity of Ca 2+ /CaM enzyme and compounds involved in changing the K + gradient across the plasma membrane thereby increasing or decreasing the membrane potential ratio (MPR™) values. The invention provides methods of identifying a compound that modulates the activity of PKC which is an important protein of the DAG signaling pathway. Methods of identifying a compound that modulates DAG and its related enzymes along the DAG signaling pathway are provided. These compounds decrease or increase the membrane potential ratio (MPR™) in BD and ADHD patients.

1 . A method of diagnosing bipolar disorder (BD) in a human patient comprising
 obtaining a test ratio of a mean membrane potential of a first population of human patient cells incubated in vitro in the presence of an agent that alters diacylglycerol signaling and in the absence of K + , to a mean membrane potential of a second population of the human patient cells incubated in vitro in the absence of the agent that alters diacylglycerol signaling and in the presence of K +  or absence of K + ;   comparing the test ratio to (a) and/or (b):   (a) is a control ratio of a mean membrane potential of control human cells known to not have said BD incubated in vitro in the presence of the agent that alters diacylglycerol signaling and in the absence of K+, to a mean membrane potential of the control human cells known incubated in vitro in the absence of the agent that alters diacylglycerol signaling and in the presence of K+ or absence of K+,   (b) is a bipolar control ratio of a mean membrane potential of bipolar control human cells known to have said BD incubated in vitro in the presence of the agent that alters diacylglycerol signaling and in the absence of K+, to a mean membrane potential of the bipolar control human cells incubated in vitro in the absence of the agent that alters diacylglycerol signaling and in the presence of K+ or absence of K+; and   diagnosing the human patient to have BD when:   (1) the test ratio is not significantly different from the control ratio of (a),   (2) the test ratio is increased towards the control ratio of (a) in comparison to the bipolar control ratio of (b), or   (3) the test ratio is increased in comparison to the bipolar control ratio of (b).   
     
     
         2 . The method of  claim 1 , wherein the agent that alters diacylglycerol signaling is selected from the group consisting of a calcium-calmodulin (Ca 2+ /CaM) kinase inhibitor, a diacylglycerol kinase inhibitor, and a protein kinase C inhibitor. 
     
     
         3 . The method of  claim 1 , wherein the agent affects calcium-activated potassium (CaK) channels. 
     
     
         4 . A method of diagnosing attention deficit hyperactivity disorder (ADHD) in a human patient comprising
 obtaining a test ratio of a mean membrane potential of a first population of human patient cells incubated in vitro in the presence of an agent that alters diacylglycerol signaling and in the absence of K+, to a mean membrane potential of a second population of the human patient cells incubated in vitro in the absence of the agent that alters diacylglycerol signaling and presence of K+ or absence of K+;   comparing the test ratio to (a) and/or (b):   (a) a control ratio of a mean membrane potential of control human cells known to not have said ADHD incubated in vitro in the presence of the agent that alters diacylglycerol signaling and in the absence of K+, to a mean membrane potential of the control human cells incubated in vitro in the absence of the agent that alters diacylglycerol signaling and in the presence of K +  or absence of K + ,   (b) an ADHD control ratio of a mean membrane potential of ADHD control human cells known to have said ADHD incubated in vitro in the presence of the agent that alters diacylglycerol signaling and in the absence of K+, to a mean membrane potential of the ADHD control human cells incubated in vitro in the absence of the agent that alters diacylglycerol signaling and in the presence of K+ or absence of K+; and   diagnosing the human patient to have ADHD when:   (1) the test ratio is not significantly different from the control ratio of (a),   (2) the test ratio is decreased towards the control ratio of (a) in comparison to the ADHD control ratio of (b), or   (3) the test ratio is decreased in comparison to the ADHD control ratio of (b).   
     
     
         5 . The method of  claim 4 , wherein the agent that alters diacylglycerol signaling is selected from the group consisting of a calcium-calmodulin (Ca 2+ /CaM) kinase inhibitor, a diacylglycerol kinase inhibitor, and a protein kinase C inhibitor. 
     
     
         6 . The method of  claim 4 , wherein the agent affects calcium-activated potassium (CaK) channels. 
     
     
         7 - 37 . (canceled) 
     
     
         38 . A method of diagnosing bipolar disorder (BD) in a human patient comprising
 obtaining a test ratio of a mean membrane potential of a first population of human patient cells that express human calcium-activated potassium-channels hSK 4 , incubated in vitro in the presence of an agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + , to a mean membrane potential of a second population of the human patient cells that express human calcium-activated potassium-channels hSK 4 , incubated in vitro in the absence of the agent that alters that express human calcium-activated potassium-channels hSK 4  activity and in the absence of K + ;   comparing the test ratio to (a) and/or (b):   (a) is a control ratio of a mean membrane potential of control human cells known to not have said BD incubated in vitro in the presence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + , to a mean membrane potential of the control human cells incubated in vitro in the absence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + ,   (b) is a bipolar control ratio of a mean membrane potential of bipolar control human cells known to have said BD incubated in vitro in the presence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + , to a mean membrane potential of the bipolar control human cells incubated in vitro in the absence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + ;   diagnosing the human patient to have BD when:   (1) the test ratio is not significantly different from the control ratio of (a),   (2) the test ratio is increased towards the control ratio of (a) in comparison to the bipolar control ratio of (b), or   (3) the test ratio is increased in comparison to the bipolar control ratio of (b).   
     
     
         39 . The method of  claim 38 , wherein the agent that alters human calcium-activated potassium-channels hSK 4  activity is ethanol, amphetamine, ephedrine, cocaine, caffeine, nicotine, methylphenidate, lithium, δ-9-tetrahydrocannibinol, phencyclidine, lysergic acid diethylamide (LSD), mescaline, or combinations thereof. 
     
     
         40 . The method of  claim 39 , wherein the agent that alters human calcium-activated potassium-channels hSK 4  activity is ethanol. 
     
     
         41 . A method of diagnosing attention deficit hyperactivity disorder (ADHD) in a human patient comprising
 obtaining a test ratio of a mean membrane potential of a first population of human patient cells that express human calcium-activated potassium-channels hSK 4 , incubated in vitro in the presence of an agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + , to a mean membrane potential of a second population of the human patient cells that express human calcium-activated potassium-channels hSK 4  incubated in vitro in the absence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + ;   comparing the test ratio to (a) and/or (b):   (a) is a control ratio of a mean membrane potential of control human cells known to not have said ADHD incubated in vitro in the presence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + , to a mean membrane potential of the control human cells incubated in vitro in the absence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + ,   (b) is a bipolar control ratio of a mean membrane potential of ADHD control human cells known to have said ADHD incubated in vitro in the presence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + , to a mean membrane potential of the ADHD control human cells incubated in vitro in the absence of the agent that alters human calcium-activated potassium-channels hSK 4  activity and in the absence of K + ; and   diagnosing the human patient to have ADHD when:   (1) the test ratio is not significantly different from the control ratio of (a),   (2) the test ratio is decreased towards the control ratio of (a) in comparison to the ADHD control ratio of (b), or   (3) the test ratio is decreased in comparison to the ADHD control ratio of (b).   
     
     
         42 . The method of  claim 41 , wherein the agent that alters human calcium-activated potassium-channels hSK 4  activity is selected from the group consisting of ethanol, amphetamine, ephedrine, cocaine, caffeine, nicotine, methylphenidate, lithium, δ-9-tetrahydrocannibinol, phencyclidine, lysergic acid diethylamide (LSD), mescaline, and combinations thereof. 
     
     
         43 . The method of  claim 42 , wherein the agent that alters human calcium-activated potassium-channels hSK 4  activity is ethanol. 
     
     
         44 . The method of  claim 1 ,  4 ,  38  or  41 , wherein the human patient cells is selected from the group consisting of red blood cells and lymphoblasts.