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Experimental febrile seizures are precipitated by a hyperthermia-induced respiratory alkalosis

Sebastian Schuchmann1, Dietmar Schmitz, Claudio Rivera

  • 1Department of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1 (POB 65), 00014 Helsinki, Finland.

Nature Medicine
|July 5, 2006
PubMed

Insights

Hyperthermia induces febrile seizures in immature brains by causing respiratory alkalosis. Controlling brain pH with CO2 prevented seizures and long-term epilepsy-related changes, suggesting new therapeutic strategies.

Area of Science:

  • Neuroscience
  • Pediatric Neurology
  • Biochemistry

Background:

  • Febrile seizures are common in children, with complex seizures increasing epilepsy risk.
  • Mechanisms triggering hyperthermic seizures remain unclear.
  • Elevated brain pH can enhance neuronal excitability.

Purpose of the Study:

  • Investigate the role of brain pH in hyperthermia-induced febrile seizures.
  • Identify triggers for febrile seizures.
  • Explore therapeutic interventions for fever-related epilepsy.

Main Methods:

  • Inducing hyperthermia in immature rat pups.
  • Measuring brain pH changes during hyperthermia.
  • Administering ambient CO2 to suppress alkalosis.
  • Assessing seizure activity and hippocampal changes (I(h) current, CB1 receptor expression).
  • Mimicking hyperthermia effects with bicarbonate injection.

Main Results:

  • Hyperthermia induced respiratory alkalosis in immature brains, with seizures occurring at a pH threshold of 0.2-0.3 units.
  • 5% ambient CO2 abolished seizures within 20 seconds.
  • CO2 prevented long-term hippocampal changes, including I(h) current and CB1 receptor upregulation.
  • Bicarbonate injection mimicked hyperthermia's effects.

Conclusions:

  • Respiratory alkalosis is a key mechanism triggering febrile seizures in immature brains.
  • Modulating brain pH offers a potential therapeutic strategy for fever-related epilepsy.
  • Understanding pH-mediated mechanisms can advance research into epileptic syndromes.

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