# Camphor-Induced Seizures in Rats Increase the Potency of Gamma Oscillations During the Ictal Period, A Component that may Lead to Refractoriness in Seizure Control

**Authors:** Priscille Fidelis Pacheco Hartcopff, Clarissa Araujo da Paz, Luciana Eiró Quirino, Thaysa de Sousa Reis, Daniella Bastos de Araujo, Rafael dos Reis de Souza, Caio Gabriel da Silva Motta, Mateus Felipe Ferreira Araújo, Marcelo Victor dos Santos Brito, Murilo Farias dos Santos, Alisson Bruno Leite Lima, Axell Lins, Moisés Hamoy

PMC · DOI: 10.1007/s12640-026-00793-3 · Neurotoxicity Research · 2026-03-24

## TL;DR

Camphor-induced seizures in rats show unique brain activity patterns and drug resistance, suggesting potential for studying seizure mechanisms and drug responses.

## Contribution

The study introduces camphor as a novel chemoconvulsant model with distinct neurobehavioral and electrocorticographic features.

## Key findings

- Camphor induces generalized seizures with distinct behavioral patterns and cortical oscillatory activity.
- Camphor-induced seizures show partial resistance to some antiepileptic drugs but respond to diazepam and propofol.
- The model resembles PTZ-induced seizures but with lower potency and unique pharmacoresistance profiles.

## Abstract

Particularly in the evaluation of substances that can cause neuronal hyperexcitability, triggering refractoriness to antiepileptic drugs, this has always been of interest to science. This study investigated the neurobehavioral and electrocorticographic (ECoG) characteristics of seizures induced by camphorated oil in Wistar rats and compared them to those triggered by pentylenetetrazol (PTZ), a classical chemoconvulsant model. Male rats received intraperitoneal administration of camphor (470 mg/kg), and behavioral evolution was monitored to characterize seizure onset and progression. ECoG recordings from the motor cortex were acquired for 30 min to assess cortical oscillatory activity during ictal and interictal periods. Camphor administration elicited six distinct and rapidly evolving behavioral patterns culminating in generalized clonic seizures with loss of postural reflexes. ECoG analyses revealed cyclic high-power ictal discharges interspersed with low-power interictal activity, resembling PTZ-induced seizures but with lower potency. Evaluation of anticonvulsant efficacy demonstrated that camphor-induced seizures were refractory to phenobarbital and phenytoin, whereas diazepam and propofol significantly reduced β- and γ-band power and effectively controlled convulsive activity. These findings suggest that camphor produces a reproducible chemoconvulsant model characterized by prominent cortical excitability and partial pharmacoresistance, supporting its potential utility in neurotoxicological and neuropharmacological studies aimed at understanding seizure mechanisms and testing antiepileptic drug responsiveness.

The online version contains supplementary material available at 10.1007/s12640-026-00793-3.

## Linked entities

- **Chemicals:** camphor (PubChem CID 2537), pentylenetetrazol (PubChem CID 5917), phenobarbital (PubChem CID 4763), phenytoin (PubChem CID 1775), diazepam (PubChem CID 3016), propofol (PubChem CID 4943)

## Full-text entities

- **Genes:** Glul (glutamate-ammonia ligase) [NCBI Gene 24957] {aka Glns}
- **Diseases:** infection (MESH:D007239), diseases (MESH:D004194), Epilepsy (MESH:D004827), irritation (MESH:D001523), pain (MESH:D010146), head and neck tremors (MESH:D006258), akinesia (MESH:C537921), organ failure (MESH:D009102), encephalopathy (MESH:D001927), West syndrome (MESH:D013036), fever (MESH:D005334), electrolyte disorders (MESH:D014883), poisoning (MESH:D011041), hypersensitivity (MESH:D004342), tremor (MESH:D014202), Seizure (MESH:D012640), inflammation (MESH:D007249), anxiety (MESH:D001007), neuronal hyperexcitability (MESH:D009410)
- **Chemicals:** Ca2+ (-), Phenobarbital (MESH:D010634), Lidocaine (MESH:D008012), GABA (MESH:D005680), ketamine (MESH:D007649), kainate (MESH:D007608), pilocarpine (MESH:D010862), Cl- (MESH:D002713), thiocolchicoside (MESH:C004280), nicotine (MESH:D009538), Depacon (MESH:D014635), SP (MESH:C000604007), Ketoprofen (MESH:D007660), Propofol (MESH:D015742), PTZ (MESH:D010433), Phenytoin (MESH:D010672), silver (MESH:D012834), xylazine hydrochloride (MESH:D014991), PVPI (MESH:D011206), caffeine (MESH:D002110), alpha-ketoglutarate (MESH:D007656), Na+ (MESH:D012964), Camphor (MESH:D002164), lithium (MESH:D008094), diisopropylfluorophosphate (MESH:D007531), Diazepam (MESH:D003975), EOs (MESH:D009822)
- **Species:** Cinnamomum camphora (camphor tree, species) [taxon 13429], Homo sapiens (human, species) [taxon 9606], Clibadium (genus) [taxon 183010], Rattus norvegicus (brown rat, species) [taxon 10116]

## Full text

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## Figures

8 figures with captions in the complete paper: https://tomesphere.com/paper/PMC13013342/full.md

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Source: https://tomesphere.com/paper/PMC13013342