Unaltered trace element levels following the absence status induction by an alpha 2A receptor agonist in the cortex and hippocampus of genetic absence epilepsy rats

Abstract

This study builds upon our prior investigation proposing a potential animal model for absence status epilepticus induced by specific alpha-2a adrenergic receptor (α2AAR) activation through intracerebroventricular injection of dexmedetomidine (DEX). Our objective was to explore trace element levels within the cortex of genetic absence epilepsy rats from Strasbourg (GAERS) during absence status induction through α2AAR activation. Stereotaxic surgery was performed on adult GAERS to implant recording electrodes in the frontoparietal cortices under anesthesia. Following intracerebroventricular injection of the α2AAR agonist, DEX, the electroencephalography (EEG) was recorded. After inducing the second period of absence statuses, the rats were euthanized. Trace elements were analyzed using inductively coupled plasma mass spectrometry (ICP/MS) among the groups: GAERS-NAÏVE, GAERS injected with saline (GAERS-SAL), and GAERS injected with DEX (GAERS-DEX). No significant differences of the levels of trace elements were observed in the GAERS-DEX group compared to GAERS-SAL following absence status induction. Conversely, significant differences in trace element levels were identified between the GAERS-NAÏVE and GAERS-SAL or GAERS-DEX groups. Cortical levels of 25Mg, 55Mn, 57Fe, 88Sr, 65Cu, 42Mo, 80Hg, 15P, 52Cr, 59Co, 66Zn, 82Se, 85Rb, 133Cs, and 205Tl were higher in the GAERS-NAÏVE group compared to GAERS-SAL (p < 0.05). Similarly, hippocampal levels of 25Mg, 43Ca, 55Mn, 57Fe, 88Sr, 65Cu, 42Mo, 80Hg, 15P, 52Cr, 59Co, 66Zn, 82Se, 85Rb, 133Cs, and 205Tl were higher in the GAERS-NAÏVE group compared to the GAERS-SAL group (p < 0.05). Our findings suggest that DEXinduced absence status does not alter trace element levels in the cortex and hippocampus, unlike convulsive forms of epilepsies. However, the influence of trace element modulations on the development of absence status remains open to discussion. Intriguingly, cannula placement appeared to affect trace element levels, prompting inquiries into the current methodology of intracerebroventricular cannula implementation.

Keywords

• GAERS
• absence status epilepticus
• trace elements
• dexmedetomidine
• alpha 2AR

References

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