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Stress and Brain 2023, 3(3): 134-145 https://doi.org/10.26599/SAB.2022.9060037
Research Article | Open Access | Issue | Published: 05 November 2023

Increased expression of galanin and its receptors in the dorsal hippocampus during epileptogenesis in a rat model of pilocarpine-induced temporal lobe epilepsy

Show Author's Information Jing Sun1,2,  Shu Xu2,3,  Xiaoxiao Li2,  Tianyi Li4,  Changqing Liu5,  Jian Zhou5,  Guoming Luan5,  Zhiqing Xu1,2( )
Department of Pathology, Capital Medical University, Beijing 100069, China
Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing 100069, China
Neurorehabilitation Center, Beijing Boai Hospital, China Rehabilitation Research Center, Beijing 100068, China
Laboratory of Translational Neuropharmacology, Department of Clinical Neuroscience, Center for Molecular Medicine L8:01, Karolinska University Hospital, Stockholm 17176, Sweden
Beijing Key Laboratory of Epilepsy, Sanbo Hospital, Capital Medical University, Beijing 100093, China
Keywords:
hippocampus, epilepsy, antiepileptic, galanin, pilocarpine
Cite this article:
Sun J, Xu S, Li X, et al. Increased expression of galanin and its receptors in the dorsal hippocampus during epileptogenesis in a rat model of pilocarpine-induced temporal lobe epilepsy. Stress and Brain, 2023, 3(3): 134-145. https://doi.org/10.26599/SAB.2022.9060037
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Abstract Full text About this article
Background:

The neuropeptide galanin has been shown to exhibit anticonvulsant effects in animal models. However, only a few studies have attempted to identify the galanin receptor subtype (s) involved in this effect. In the present study, the expression of galanin and that of its receptors in a rat model of temporal lobe epilepsy was studied to reveal the epileptogenesis-related alterations.

Methods:

Pilocarpine-inducted status epilepticus (SE) rat model was used for temporal lobe epilepsy. Galanin and galanin receptor mRNA was detected by Real-time polymerase chain reaction in dorsal hippocampus of rats at three different time points following SE: at the acute phase (24h), latent period (7 days), and chronic epileptic period (8 weeks). Using immunohistochemistry, galanin positive fibers and bodies were also observed.

Results:

In the acute seizure phase, a significant up-regulation of the galanin mRNA was observed in the hippocampus. Meanwhile, galanin-positive cells appeared, while galanin-positive fibers disappeared in the hilus of the dentate gyrus, stratum radiatum of CA1, and stratum lucidum of CA3, indicating an increase in galanin synthesis and release during the acute seizure phase. The gene expression analysis also indicated a significant increase in the transcription of galanin receptors GalR1 and GalR3 24h after SE. The increased levels of GalR1 mRNA were also observed in the latent and chronic epileptic periods.

Conclusion:

In general, these data suggest that adaptive changes occur in the galanin system during epileptogenesis that may affect its antiepileptic effects. Furthermore, these changes should be taken into account when attempting to pharmacologically modulate this system.


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Abstract
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About this article

Increased expression of galanin and its receptors in the dorsal hippocampus during epileptogenesis in a rat model of pilocarpine-induced temporal lobe epilepsy

Show Author's information Jing Sun1,2, Shu Xu2,3, Xiaoxiao Li2, Tianyi Li4, Changqing Liu5, Jian Zhou5, Guoming Luan5, Zhiqing Xu1,2( )
Department of Pathology, Capital Medical University, Beijing 100069, China
Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing 100069, China
Neurorehabilitation Center, Beijing Boai Hospital, China Rehabilitation Research Center, Beijing 100068, China
Laboratory of Translational Neuropharmacology, Department of Clinical Neuroscience, Center for Molecular Medicine L8:01, Karolinska University Hospital, Stockholm 17176, Sweden
Beijing Key Laboratory of Epilepsy, Sanbo Hospital, Capital Medical University, Beijing 100093, China

Abstract

Background:

The neuropeptide galanin has been shown to exhibit anticonvulsant effects in animal models. However, only a few studies have attempted to identify the galanin receptor subtype (s) involved in this effect. In the present study, the expression of galanin and that of its receptors in a rat model of temporal lobe epilepsy was studied to reveal the epileptogenesis-related alterations.

Methods:

Pilocarpine-inducted status epilepticus (SE) rat model was used for temporal lobe epilepsy. Galanin and galanin receptor mRNA was detected by Real-time polymerase chain reaction in dorsal hippocampus of rats at three different time points following SE: at the acute phase (24h), latent period (7 days), and chronic epileptic period (8 weeks). Using immunohistochemistry, galanin positive fibers and bodies were also observed.

Results:

In the acute seizure phase, a significant up-regulation of the galanin mRNA was observed in the hippocampus. Meanwhile, galanin-positive cells appeared, while galanin-positive fibers disappeared in the hilus of the dentate gyrus, stratum radiatum of CA1, and stratum lucidum of CA3, indicating an increase in galanin synthesis and release during the acute seizure phase. The gene expression analysis also indicated a significant increase in the transcription of galanin receptors GalR1 and GalR3 24h after SE. The increased levels of GalR1 mRNA were also observed in the latent and chronic epileptic periods.

Conclusion:

In general, these data suggest that adaptive changes occur in the galanin system during epileptogenesis that may affect its antiepileptic effects. Furthermore, these changes should be taken into account when attempting to pharmacologically modulate this system.

Keywords: hippocampus, epilepsy, antiepileptic, galanin, pilocarpine

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Publication history

Received: 08 August 2022
Revised: 13 October 2023
Accepted: 13 October 2023
Published: 05 November 2023
Issue date: November 2023

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© The Author(s) 2023

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