Objective A significant number of epileptic patients fail to respond to available anticonvulsive medications. To find new anticonvulsive medications, we evaluated FDA‐approved drugs not known to be anticonvulsants. Using zebrafish larvae as an initial model system, we found that the opioid antagonist naltrexone exhibited an anticonvulsant effect. We validated this effect in three other epilepsy models and present naltrexone as a promising anticonvulsive candidate. Methods Candidate anticonvulsant drugs, determined by our prior transcriptomics analysis of hippocampal tissue, were evaluated in a larval zebrafish model of human Dravet syndrome (scn1Lab mutants), in wild‐type zebrafish larvae treated with the pro‐convulsant drug pentylenetetrazole (PTZ), in wild‐type C57bl/6J acute brain slices exposed to PTZ, and in wild‐type mice treated with PTZ in vivo. Abnormal locomotion was determined behaviorally in zebrafish and mice and by field potential in neocortex layer IV/V and CA1 stratum pyramidale in the hippocampus. Results The opioid antagonist naltrexone decreased abnormal locomotion in the larval zebrafish model of human Dravet syndrome (scn1Lab mutants) and wild‐type larvae treated with the pro‐convulsant drug PTZ. Naltrexone also decreased seizure‐like events in acute brain slices of wild‐type mice, and the duration and number of seizures in adult mice injected with PTZ. Significance Our data reveal that naltrexone has anticonvulsive properties and is a candidate drug for seizure treatment.

Measurement of neuronal size is challenging due to their complex histology. Current practice includes manual or pseudo-manual measurement of somatic areas, which is labor-intensive and prone to human biases and intra-/inter-observer variances. We developed a novel high-throughput neuronal morphology analysis framework (ANMAF), using convolutional neural networks (CNN) to automatically contour the somatic area of fluorescent neurons in acute brain slices. Our results demonstrate considerable agreements between human annotators and ANMAF on detection, segmentation, and the area of somatic regions in neurons expressing a genetically encoded fluorophore. However, in contrast to humans, who exhibited significant variability in repeated measurements, ANMAF produced consistent neuronal contours. ANMAF was generalizable across different imaging protocols and trainable even with a small number of humanly labeled neurons. Our framework can facilitate more rigorous and quantitative studies of neuronal morphology by enabling the segmentation of many fluorescent neurons in thick brain slices in a standardized manner.

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Objective Many seizing neonates fail to respond to first‐line anticonvulsant medications. Phenobarbital, an allosteric modulator of γ‐aminobutyric acid type A (GABAA) receptors, has low efficacy in treating neonatal seizures and causes neuronal apoptosis. Nonetheless, it is one of the most used anticonvulsants in this age group. In neonatal mice, phenobarbital's poor effectiveness is due in part to high intraneuronal chloride concentration, which causes GABA to exert depolarizing actions. Therefore, another approach to treat neonatal seizures could be to use anticonvulsants that do not rely on GABAergic modulation. We evaluated whether lacosamide decreases seizures in neonatal mice and whether it increases apoptosis in vitro and in vivo. Methods In vitro, we measured the effect of different lacosamide concentrations on seizure‐like activity induced by the pro‐convulsant drug 4‐aminopyridine in neocortical brain slices (layer IV/V) from neonatal (postnatal day 8–11) and adult (1–1.6 months old) C57BL/6J mice. In vivo, we recorded the effect of different lacosamide concentrations on neonatal behavioral seizures induced by kainic acid. We studied neocortical apoptosis in vitro and in vivo, measuring terminal deoxynucleotidyl transferase (TdT) dUTP nick‐end labeling signal and cleaved‐caspase 3. Results Lacosamide reduced epileptiform activity in neocortical brain slices of neonates and adults in a concentration‐dependent manner. In vivo, lacosamide reduced the duration and number of behavioral seizures. Lacosamide did not increase total or neuronal apoptosis in the neocortex in vitro or in vivo. Significance Lacosamide reduces neocortical seizure‐like activity in neonatal mice in vitro and in vivo without an acute increase in apoptosis. Our results support the use of lacosamide to treat neonatal seizures, with the advantage of not increasing apoptosis acutely.