C-Fos mapping and EEG characteristics of multiple mice brain regions in pentylenetetrazol-induced seizure mice model

ABSTRACT

Purpose: To confirm different local brain activities characterized in pentylenetetrazol (PTZ)-induced seizure model.

Methods: we induced seizure response by a single dose of PTZ injection (45 mg/kg, i.p.). Local activity was recorded in different brain regions by EEG in time and c-Fos staining at different time points (0.5 h, 1 h, 2 h, 4 h) after PTZ treatment.

Results: EEG recordings showed distinctive features of activation in different brain areas. With the aggravation of behavioral manifestations of seizures, the frequency and amplitude of the discharges on EEG were increasing gradually. The epileptic response on EEG immediately ended after reaching the maximum stage of seizures, followed by a short period of suppression. The labeling of c-Fos was enhanced in the medial prefrontal cortex, the piriform cortex, the amygdala, hippocampal CA1, CA3 and dentate gyrus, but inapparent in the striatum. The most potent changes in c-Fos were observed in cortex, amygdala nuclei, and dentate gyrus. EEG and c-Fos immunolabeling in neuronal activation showed discrepancies in the striatum. For each brain region, the maximum c-Fos labeling was observed at 2 h after injection and diminished at 4 h. The level of c-Fos immunoreactivity was even lower than the control group, which was accompanied by increased labeling of parvalbumin neurons (PVNs).

Conclusions: These findings validated PTZ-induced seizure as a seizure model with a specific spatial-temporal profile. Neuronal activity was enhanced and then subsequently inhibited during seizure evolution.

Abbreviations: AEDs: anti-epileptic drugs; AF: Alexa Fluor; CA1: Cornu Ammonis area 1; CA3: Cornu Ammonis area 3; DAB, 3: 3P-diaminobenzidine; DAPI: 4‘,6-diamidino-2-phenylindole; DG: dentate gyrus; EEG: electroencephalogram; GABA: gamma-aminobutyric acid; IEG: immediate early gene; mPFC: medial prefrontal cortex; NAc: nucleus accumbens; PB: phosphate buffer; PBS: phosphate buffered saline; PBST: phosphate buffered saline with Tween; PFA, paraformaldehyde; PTZ: pentylenetetrazol; PVN: parvalbumin neuron; ROI: regions of interest; SE: status epilepticus.

KEYWORDS:

• C-Fos mapping
• EEG characteristics
• brain regions
• pentylenetetrazol-induced seizures
• neural activation

Acknowledgments

We would like to acknowledge Global Biotech Co. Ltd for providing electrode arrays for EEG recordings of multiple brain regions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by National Key R&D Program of China [2017YFC1307500]; Beijing-Tianjin-Hebei Cooperative Basic Research Program [H2018206435]; Capital Healthy Development Research Funding [2016-1-2011]; Natural Foundation of Capital Medical university [PYZ2017132]; Beijing Key Laboratory on Clinical study of Epilepsy [2016DXBL02], Center for CNS Drug Discovery.

Notes on contributors

Huajun Yang

Huajun Yang is a Ph.D. candidate in neurology in Beijing Tiantan Hospital, Capital Medical University. His research work focuses on electrophysiological profile and pathogenesis of epilepsy.

Wei Shan

Wei Shan, work in Department of Neurology, Beijing Tiantan Hospital, Capital Medical University.

Fei Zhu

Fei Zhu is a physician in the Department of Neurology, Beijing Tiantan Hospital, Capital Medical University.

Tingting Yu

Tingting Yu is a postgraduate student in neurology in Beijing Tiantan Hospital, Capital Medical University.

Jingjing Fan

Jingjing Fan is a Ph.D. candidate in neurology in Beijing Tiantan Hospital, Capital Medical University.

Anchen Guo

Anchen Guo is a specialist in neurology in National Center for Clinical Medicine of Neurological Diseases.

Fei Li

Fei Li is a professor in Beijing Institute of pharmacology and toxicology, Beijing, 100050, P.R.China

Xiaofeng Yang

Xiaofeng Yang is a professor in neurology in Beijing Institute for Brain Disorders.

Qun Wang

Qun Wang is a professor in neurology and Director of Epilepsy Center, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University. His research interests include pathophysiology and clinical pharmacology of epilepsy and associated comorbidities.