Neurochemical abnormalities in the hippocampus of male rats displaying audiogenic seizures, a genetic model of epilepsy

• Published in: Neuroscience letters Vol. 761; p. 136123
• Main Authors: dos Santos, Rodrigo Ribeiro, Bernardino, Túlio C., da Silva, Maria Carolina Machado, de Oliveira, Antônio C.P., Drumond, Luciana E., Rosa, Daniela V., Massensini, André R., Moraes, Márcio F.D., Doretto, Maria C., Romano-Silva, Marco A., Reis, Helton J.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 14.09.2021
• Subjects: Animals; Calcium - metabolism; Epilepsy; GABA; gamma-Aminobutyric Acid - metabolism; Glutamate; Glutamic Acid - metabolism; Hippocampus - metabolism; Male; Neuronal Calcium-Sensor Proteins - metabolism; Neuropeptides - metabolism; Rats; Rats, Wistar; Seizures - metabolism; Synaptosomes - metabolism; Wistar audiogenic rats; GABA; Wistar audiogenic rats; Glutamate; Epilepsy
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2021.136123

•Glutamate release is reduced in hippocampal synaptosomes of WAR.•GABA release is reduced in hippocampal synaptosomes of WAR.•Glutamate uptake is reduced in hippocampal synaptosomes of WAR.•NCS-1 expression of WAR differs from controls. Epilepsy is a disorder characterized by recurrent seizures that affects 1% of the population. However, the neurochemical alterations observed in epilepsy are not fully understood. There are different animal models of epilepsy, such as genetic or drug induced. In the present study, we utilize Wistar Audiogenic Rats (WAR), a murine strain that develops seizures in response to high intensity audio stimulation, in order to investigate abnormalities in glutamatergic and GABAergic systems. Synaptosomes and glial plasmalemmal vesicles were prepared from hippocampus and cortex, respectively. Glutamate and GABA release and uptake were assayed by monitoring the fluorescence and using L-[3H]-radiolabeled compounds. Glutamate and calcium concentration in the synaptosomes were also measured. The expression of neuronal calcium sensor 1 (NCS-1) was determined by western blot. Glutamate and GABA release evoked by KCl was decreased in WAR compared to control Wistar rats. Calcium independent release was not considerably different in both groups. The total amount of glutamate of synaptosomes, as well as glutamate uptake by synaptosomes and GPV were also decreased in WAR in comparison with the controls. In addition, [Ca2+]i of hippocampal synaptosomes, as well as NCS-1 expression in the hippocampus, were increased in WAR in comparison with controls. In conclusion, our results suggest that WAR have important alterations in the glutamatergic and GABAergic pathways, as well as an increased expression of NCS-1 in the hippocampus and inferior colliculus. These alterations may be linked to the spreading of hyperexcitability and recruitment of various brain regions.