It has been extremely difficult to screen for drugs that prevent epilepsy after brain injury, because spontaneous recurrent seizures begin gradually and the interval between seizures varies widely, so that long-term, intensive seizure monitoring is required to determine whether a drug prevents epilepsy. A rigorous yet rapid screen would enable us to test many promising compounds for anti-epileptogenic properties, and would provide epilepsy researchers with a much-needed assay to test new compounds developed within their laboratories. We have developed a new set of technologies to enable large-scale screening for antiepileptic drugs. In collaboration with the Harvard Center for Engineering in Medicine, we have developed an in vitro model of epileptogenesis comprised of glass chips that can be used to culture, record from, and administer drugs to arrays of 32 organotypic brain slices per chip. We have recently shown that these brain slice cultures undergo a rapid, predictable process of epileptogenesis, and that the organotypic brain slices respond to anticonvulsant drugs just as human patients do. We have recently published computer algorithms for continuously recording and quantifying electrographic spikes and seizures, and in collaboration with Ed Dudek, an investigator in the National Institute of Neurological Diseases and Stroke (NINDS) Anticonvulsant Screening Program, we have validated these algorithms in two in vivo models of epileptogenesis as well as in the in vitro model. We will use our newly-created technologies to execute large-scale, parallel screening of drug libraries for agents that prevent, reduce, or reverse epileptogenesis. One such library is the NINDS Custom Compounds library; we will focus on the 561 compounds that have already been approved by the FDA. We propose to subject these compounds to a rapid, rigorous two stage screen for anti-epileptogenic properties. In the first stage, we will screen compounds using parallel cultured brain slice assays. Compounds that prevent, reduce, or reverse epileptogenesis will then progress to the second stage, in which the most promising compounds will be subjected to a more rigorous albeit much slower second assay, the kainate model of epileptogenesis. In both stages, electrographic seizure activity will be assayed quantitatively using continuously recorded and analyzed EEG data. This research will lead to a U01. The results of the R21-funded screening project may produce compounds that are sufficiently active to begin clinical testing. Alternatively, the R21 will provide lead compounds that will enable us to apply for the NINDS Blueprint Grand Challenge for New Drugs for Diseases and Disorders of the Nervous System, so that we can screen larger compound libraries and optimize compounds in collaboration with the medicinal chemists at The Laboratory for Drug Discovery in Neurodegeneration (LDDN) in the Harvard NeuroDiscovery Center. PUBLIC HEALTH RELEVANCE: It has not been possible to screen for drugs that prevent epilepsy after brain injury, because seizures begin to occur very gradually, and the interval between seizures varies widely, so that long-term, intensive seizure monitoring is required to determine whether a drug prevents epilepsy. We have developed a set of technologies that makes possible the application of large-scale screening strategies to this problem. Cultured brain slices that become spontaneously epileptic will be deployed in a highly parallel screening program as a first stage in screening. In vivo testing will be used to confirm the effects of the most promising agents found in the first stage of screening.