Neural Activity Correlates With Behavior Effects of Anti-Seizure Drugs Efficacy Using the Zebrafish Pentylenetetrazol Seizure Model

Abstract

Approximately 30% of patients with epilepsy do not achieve adequate seizure control through current anti-seizure drugs and treatment methods. Therefore, a critical need exists to efficiently screen anti-seizure drugs to enhance our ability to tailor treatment protocols and improve patient outcomes. The zebrafish pentylenetetrazol (PTZ) seizure model has become an increasingly popular screening paradigm for novel anti-seizure compounds. However, previous research using this model was variable due to differing experimental methods. Here, we present a method that was optimized to improve reliability and reproducibility in our laboratory using this PTZ model to develop a more robust screening of anti-seizure drugs comparing behavior and neural activity. Our behavior assay, spanning 90 min using 10 mM PTZ on 7 days post fertilization zebrafish, provides a broad window to observe anti-seizure drug efficacy. To compare our method with previously published data, we tested carbamazepine, lamotrigine, and topiramate, which have been tested in previous PTZ zebrafish assays. In addition, we assessed the candidate anti-seizure compound GS967, which has not been previously tested in the zebrafish seizure model. We examined the efficacy of anti-seizure drugs by acute administration concurrent with PTZ application and by pretreatment prior to exposure with PTZ. Pretreatment permitted us to examine potential neuroprotection and determine whether treatment time affects anti-seizure drugs’ responses. As independent validation of anti-seizure drugs’ effects, we evaluated whether the anti-seizure drug efficacy in the behavioral assay correlated with neural activity measurements, using electroencephalogram (EEG) and calcium signaling using GCaMP. There was no significant difference in the reduction of PTZ-induced seizure behavior activity between the pretreatment groups and acute treatment groups. Acute treatment with anti-seizure drugs in the EEG and GCaMP assays from 15 to 30 min post-anti-seizure drug exposure revealed consistent results between behavioral, EEG, and GCaMP assays for two of the three anti-seizure drugs. Lamotrigine only reduced neural activity (EEG and GCaMP assays). Carbamazepine, topiramate, and GS967 reduced activity in all three assays. The findings show that EEG and GCaMP assays largely correlate with the behavior findings, helping us connect physiological and behavior responses to anti-seizure drug and better assess anti-seizure drug efficacy.

Establishment of innovative ZebVortrack behavioral analysis system for quantitative epileptic seizure assessment in larval zebrafish

“…In this experiment, the ZebVortrack system was used to evaluate a variety of antiseizure drugs, and the results showed that these antiseizure drugs could reduce the activity frequency of larval zebra sh and suppress the seizure-like behavior induced by PTZ, which is in accordance with previous reports [34][35][36][37] .…”

Caffeine Decreases Topiramate Levels in Zebrafish Larvae in a Pentylenetetrazol-Induced Seizure Model

“…Contrary to the findings of Afrikanova et al, who reported inconsistencies in locomotor behavior and electroencephalogram results [ 16 ], the study by Zhang et al revealed a harmonious reduction in both behavioral and neural activity, meticulously analyzed through electroencephalogram and GCaMP studies [ 19 ]. These nuanced observations contribute valuable insights into the multifaceted effects of TPM on zebrafish larvae, emphasizing the significance of considering developmental stages and exposure durations in elucidating the compound’s impact.…”

“…Examining the anticonvulsant properties of TPM, 7 dpf larvae exhibited suppressed seizure-like behavior following an 18 h incubation with a 200 μM dose. Intriguingly, this suppression did not extend to the total seizure duration in the electroencephalogram assay [ 16 ] Further insights from a separate study indicated that both prolonged incubation and acute exposure to TPM (200 μM) resulted in conspicuous reductions in locomotor activity in 7 dpf zebrafish [ 19 ]. In the PTZ-induced seizure model (10 mM), the total movement was significantly diminished in both TPM-pretreated and acutely exposed groups compared to the controls.…”

“…In the PTZ-induced seizure model (10 mM), the total movement was significantly diminished in both TPM-pretreated and acutely exposed groups compared to the controls. The use of a lower PTZ dose (10 mM) over an extended period was a deliberate choice to mitigate the risk of synaptic fatigue, exhaustion, and mortality associated with higher PTZ concentrations, which can lead to a decline in swimming behavior at later time increments [ 19 ].…”

“…Our findings were that a 75 μM dose of TPM significantly defended larvae against PTZ, but did not reduce activity to the levels of the control, which lines up with results in 7 dpf larvae (180 μM, 18 h exposure) [ 16 ]. In 7 dpf larvae, 24 h TPM exposure (200 μM) reduced the activity to the control level [ 19 ].…”