Allopregnanolone and perampanel as adjuncts to midazolam for treating diisopropylfluorophosphate-induced status epilepticus in rats

Ashish Dhir, Donald A. Bruun, Michelle Guignet, Yi Hua Tsai, Eduardo González, Jonas Calsbeek, Joan Vu, Naomi Saito, Daniel J. Tancredi, Danielle J. Harvey, Pamela J. Lein, Michael A. Rogawski

Research output: Contribution to journalArticlepeer-review

Abstract

Combinations of midazolam, allopregnanolone, and perampanel were assessed for antiseizure activity in a rat diisopropylfluorophosphate (DFP) status epilepticus model. Animals receiving DFP followed by atropine and pralidoxime exhibited continuous high-amplitude rhythmical electroencephalography (EEG) spike activity and behavioral seizures for more than 5 hours. Treatments were administered intramuscularly 40 min after DFP. Seizures persisted following midazolam (1.8 mg/kg). The combination of midazolam with either allopregnanolone (6 mg/kg) or perampanel (2 mg/kg) terminated EEG and behavioral status epilepticus, but the onset of the perampanel effect was slow. The combination of midazolam, allopregnanolone, and perampanel caused rapid and complete suppression of EEG and behavioral seizures. In the absence of DFP, animals treated with the three-drug combination were sedated but not anesthetized. Animals that received midazolam alone exhibited spontaneous recurrent EEG seizures, whereas those that received the three-drug combination did not, demonstrating antiepileptogenic activity. All combination treatments reduced neurodegeneration as assessed with Fluoro-Jade C staining to a greater extent than midazolam alone, and most reduced astrogliosis as assessed by GFAP immunoreactivity but had mixed effects on markers of microglial activation. We conclude that allopregnanolone, a positive modulator of the GABAA receptor, and perampanel, an AMPA receptor antagonist, are potential adjuncts to midazolam in the treatment of benzodiazepine-refractory organophosphate nerve agent–induced status epilepticus.

Original languageEnglish (US)
Pages (from-to)183-206
Number of pages24
JournalAnnals of the New York Academy of Sciences
Volume1480
Issue number1
DOIs
StatePublished - Nov 17 2020

Keywords

  • AMPA receptor antagonist
  • benzodiazepine
  • GABA receptor positive allosteric modulator
  • neuroactive steroid
  • organophosphate nerve agent
  • status epilepticus

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • History and Philosophy of Science

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