Department of Pharmacology, University of Virginia, Charlottesville, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, United States
George MPR Souza
Department of Pharmacology, University of Virginia, Charlottesville, United States
Adam C Lu
Department of Pharmacology, University of Virginia, Charlottesville, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, United States
Matthew L Ritger
Department of Pharmacology, University of Virginia, Charlottesville, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, United States
Patrice Guyenet
Department of Pharmacology, University of Virginia, Charlottesville, United States
Hyperventilation reliably provokes seizures in patients diagnosed with absence epilepsy. Despite this predictable patient response, the mechanisms that enable hyperventilation to powerfully activate absence seizure-generating circuits remain entirely unknown. By utilizing gas exchange manipulations and optogenetics in the WAG/Rij rat, an established rodent model of absence epilepsy, we demonstrate that absence seizures are highly sensitive to arterial carbon dioxide, suggesting that seizure-generating circuits are sensitive to pH. Moreover, hyperventilation consistently activated neurons within the intralaminar nuclei of the thalamus, a structure implicated in seizure generation. We show that intralaminar thalamus also contains pH-sensitive neurons. Collectively, these observations suggest that hyperventilation activates pH-sensitive neurons of the intralaminar nuclei to provoke absence seizures.
