Diverse perspectives in zebrafish seizure models: An exploration of chemical inducers

Abstract

Numerous studies have investigated seizures in zebrafish, employing diverse methods to induce and observe epilepsy. Chemical inducers have become indispensable tools for precisely manipulating neural activity in controlled experiments. This research is dedicated to a meticulous comparison and analysis of various seizure-inducing chemicals in zebrafish. The selected chemical inducers include pentylenetetrazole (PTZ), kainic acid (KA), picrotoxin (PTX), pilocarpine, and other substances. The primary mechanism of these inducers involves altering neurotransmitter receptors, particularly GABA and glutamate, at inhibitory or excitatory synapses. This alteration creates an imbalance between inhibitory and excitatory signals in the brain, contributing to epileptogenesis. The resulting hyperactivity in the zebrafish brain disrupts metabolism, elevates reactive oxygen species (ROS), and causes neuronal damage. Chemical induction offers valuable insights into the neurological activity of zebrafish, enabling the observation of behaviors such as whole-body contractions, loss of posture, or freezing. Various parameters can be adjusted to examine the effects of chemical inducers on zebrafish development and to replicate various types of seizures, such as status epilepticus and temporal lobe epilepsy. Despite the array of options available, many chemical inducers remain underutilized in zebrafish studies. To ensure the successful induction of models, monitoring gene expression markers such as c-fos, which represents neuronal activity, becomes crucial. Additionally, a scoring system is employed to analyze seizure severity and identify treatment efficacy. The existing gaps in utilizing chemical inducers present great opportunities for future model development. This chemically-induced seizure model in zebrafish is pivotal for unraveling seizure mechanisms, contributing significantly to advancements in neurological research.