Method of identifying therapeutic agents for the treatment of epilepsy
The present invention relates to a method of identifying agents suitable for use in treating epilepsy and other brain disorders, including but not limited to bipolar disorder, schizophrenia and depression. The invention further relates to methods of treatment based on the use of agents so identifiable.
1. A method of identifying a candidate anti-epileptic agent comprising screening test compounds for their ability to modulate the number of synaptic vesicles at excitatory synapses that are functionally available to participate in synaptic transmission during an episode of repetitive synaptic use, wherein a test compound that reduces the number of said synaptic vesicles is a candidate anti-epileptic agent.
2. The method according to claim 1 wherein the number of said synaptic vesicles is determined optically.
3. The method according to claim 1 wherein the number of said synaptic vesicles is determined biochemically.
4. The method according to claim 1 wherein said method is effected using cultured neurons.
5. The method according to claim 4 wherein said neurons are harvested from a mammal transgenically altered to express synapto-pHluorins.
6. The method according to claim 4 wherein the number of synaptic vesicles is determined by a method comprising transfecting said neurons with a nucleic acid encoding a protein that is targeted to synaptic vesicles and that fluoresces when synaptic vesicles undergo exocytosis.
7. The method according to claim 4 wherein said synaptic vesicles are labeled with an externally applied dye during a period when said synaptic vesicles undergo endocytosis.
8. The method according to claim 1 wherein the number of said synaptic vesicles is determined by a method that comprises measuring the amount of neurotransmitter that is released upon depolarization, wherein a test compound that reduces the number of said synaptic vesicles reduces the amount of neurotransmitter released.
9. The method according to claim 8 wherein said neurotransmitter is glutamate.
10. A method of identifying a candidate anti-epileptic agent comprising screening test compounds for their ability to modulate the number of synaptic vesicles at excitatory synapses, but not at inhibitory synapses, that are functionally available to participate in synaptic transmission during repetitive synaptic use, wherein a test compound that reduces the number of said synaptic vesicles at excitatory synapses, but not at inhibitory synapses, is a candidate anti-epileptic agent.
11. A method of identifying a candidate anti-epileptic agent comprising screening test compounds for their ability to modulate the number of synaptic vesicles differentially at excitatory versus inhibitory synapses that are functionally available to participate in synaptic transmission during repetitive synaptic use, wherein a test compound that reduces the number of said synaptic vesicles differentially at excitatory versus inhibitory synapses is a candidate anti-epileptic agent.