Striatal degeneration alters absence seizures during epileptogenesis: Is nigro-striatal pathway involved in spike-and-wave discharges?


Yavuz M. , Toplu A., Çulpan Y., Turgan Aşık Z. N. , Karamahmutoğlu T., Gülçebi İdriz Oğlu M., ...More

34. International Epilepsy Conference, 28 August - 01 September 2021

  • Publication Type: Conference Paper / Summary Text

Abstract

Purpose: The increase in the nigrostriatal dopaminergic activity and the generation of spike-and-wave discharges (SWDs), which are typical absence seizures, show an inverse proportion (1,2). We aim to investigate the effect of degeneration of the nigro-striatal pathway on SWDs, during the development process- epileptogenesis- of absence epilepsy, which is characterized by non-convulsive seizures.

Method: 8 μg dose of 6-hydroxydopamine (6-OHDA) was injected to degenerate the striatum of 30-day-old rats with genetic absence epilepsy (GAERS) (striatum two injections; AP: -0.5 mm/ -1.0, ML: -3.0 mm, V: -6.0 mm). In the control group, saline was administered to the same areas (Sham). At the third week, behavioral tests were performed with apomorphine injection. Stereotaxic surgery under ketamine and xylazine anesthesia were performed in 6-OHDA and sham group GAERS with positive rotation behavior when they were three months old, and EEG recording electrodes were placed over the skull. After a one-week recovery period, basal EEGs were recorded from the animals and SWD parameters were evaluated.

Result: As a result of 6-OHDA administration to the striatum, the cumulative duration (F(2,11)=9.287; P=0.004) and mean duration (F(2,11)=6, 396; P=0.014) of SWDs were statistically lower comparing to the control groups. Striatum injections caused a deterioration in the form of SWDs.

Conclusions: The loss of striatal dopaminergic neurons seem to lead an impairment in SWD formation. It is known that the striatum may be an intermediate step in the generalization of seizures. In light of these findings, it is aimed to evaluate the SWD properties with advanced analysis.
Supported by TUBITAK-SBAG218S653.

1-Birioukova LM, et al. Compensatory Changes in the Brain Dopaminergic System of WAG/Rij Rats Genetically Predisposed to Absence Epilepsy. Bull Exp Biol Med. 2016 Sep;161(5):662-665.
2-de Bruin NM, et al. Dopamine characteristics in different rat genotypes: the relation to absence epilepsy. Neurosci Res. 2000 Oct;38(2):165-73.