AsHC 360 Exposure Influence on Epileptiform Discharges in Hippocampus of Infantile Male Rats In Vitro

Abstract

Arsenic-containing hydrocarbons (AsHCs) are typical arsenolipids found in various marine organisms. They can penetrate the blood–brain barrier, specifically affecting synaptic plasticity and the learning and memory ability of hippocampal neurons. Temporal lobe epilepsy often occurs in the hippocampus. Thus, the possible influence of AsHCs exposure to temporal lobe epilepsy garnered attention. The present study investigated the effects of epileptiform discharges (EDs) signals introduced by low-magnesium ACSF in the hippocampus of infantile male rats in vitro, using electrophysiological techniques with multi-electrode arrays under AsHC 360 exposure. In our study of the effects of AsHC 360 on EDs signals, we found that inter-ictal discharges (IIDs) were not significantly impacted. When AsHC 360 was removed, any minor effects observed were reversed. However, when we examined the impact of AsHC 360 on ictal discharges (IDs), distinct patterns emerged based on the concentration levels. For low-concentration groups (5, 20, 60 μg As L−1), both the frequency and duration effects on IDs returned to normal post-elimination of AsHC 360. However, this recovery was not evident for concentrations of 100 μg As L−1 or higher. IDs were only observed in EDs signals during exposures to AsHC 360 concentrations up to 60 μg As L−1. In these conditions, ID frequencies significantly enhanced with the increased of AsHC 360 concentration. At high concentrations of AsHC 360 (≥100 μg As L−1), the transition from IIDs or pre-ictal discharges (PIDs) to IDs was notably inhibited. Additional study on co-exposure of AsHC 360 (100 μg As L−1) and agonist (10 nM (S)-(-)-Bay-K-8644) indicated that the regulation of EDs signals under AsHC 360 exposure could be due to directly interference with the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) expression which influences the binding of excitatory glutamate neurotransmitter to AMPAR. The results suggest that EDs activities in the hippocampus of infantile Sprague Dawley rats are concentration-dependent on AsHC 360 exposure. Thus, it provides a basis for the seafood intake with AsHCs for epileptic patients and those with potential seizures.