Persistently modified h-channels after complex febrile seizures convert the seizure-induced enhancement of inhibition to hyperexcitability
Kang Chen1, 2, Ildiko Aradi1, Niklas Thon1, Mariam Eghbal-Ahmadi1, 2, Tallie Z. Baram1, 2
& Ivan Soltesz1
1
Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, California, USA
2
Department of Pediatrics, University of California at Irvine, Irvine, California, USA
Correspondence should be addressed to Ivan Soltesz isoltesz@uci.edu
Febrile seizures are the most common type of developmental seizures, affecting up to 5% of children. Experimental complex febrile seizures involving the immature rat hippocampus led to a persistent lowering of seizure threshold despite an upregulation of inhibition. Here we provide a mechanistic resolution to this paradox by showing that, in the hippocampus of rats that had febrile seizures, the long-lasting enhancement of the widely expressed intrinsic membrane conductance Ih converts the potentiated synaptic inhibition to hyperexcitability in a frequency-dependent manner. The altered gain of this molecular inhibition−excitation converter reveals a new mechanism for controlling the balance of excitation−inhibition in the limbic system. In addition, here we show for the first time that h-channels are modified in a human neurological disease paradigm.
