Systemic administration of ivabradine, a hyperpolarization‐activated cyclic nucleotide‐gated channel inhibitor, blocks spontaneous absence seizures

Abstract

Objective: Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are known to be involved in the generation of absence seizures (ASs), and there is evidence that cortical and thalamic HCN channel dysfunctions may have a proabsence role. Many HCN channel blockers are available, but their role in ASs has been investigated only by localized brain injection or in in vitro model systems due to their limited brain availability. Here, we investigated the effect on ASs of orally administered ivabradine (an HCN channel blocker approved for the treatment of heart failure in humans) following injection of the P-glycoprotein inhibitor elacridar, which is known to increase penetration into the brain of drug substrates for this efflux transporter. The action of ivabradine was also tested following in vivo microinjection into the cortical initiation network (CIN) of the somatosensory cortex and in the thalamic ventrobasal nucleus (VB) as well as on cortical and thalamocortical neurons in brain slices. Methods: We used electroencephalographic recordings in freely moving Genetic Absence Epilepsy Rats From Strasbourg (GAERSs) to assess the action of oral administration of ivabradine, with and without elacridar, on ASs. Ivabradine was also microinjected into the CIN and VB of GAERSs in vivo and applied to Wistar CIN and GAERS VB slices while recording patch-clamped cortical Layer 5/6 and thalamocortical neurons, respectively. Results: Oral administration of ivabradine markedly and dose-dependently reduced ASs. Ivabradine injection into CIN abolished ASs and elicited small-amplitude 4–7-Hz waves (without spikes), whereas in the VB it was less potent. Moreover, ivabradine applied to GAERS VB and Wistar CIN slices selectively decreased HCN channel-dependent properties of cortical Layer 5/6 pyramidal and thalamocortical neurons, respectively. Significance: These results provide the first demonstration of the antiabsence action of a systemically administered HCN channel blocker, indicating the potential of this class of drugs as a novel therapeutic avenue for ASs.

Publication DOI: https://doi.org/10.1111/epi.16926
Divisions: College of Health & Life Sciences
College of Health & Life Sciences > Aston Pharmacy School
College of Health & Life Sciences > Clinical and Systems Neuroscience
Additional Information: © 2021 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Funding: Wellcome Trust, Grant/Award Number: 91882; Országos Tudományos Kutatási Alapprogramok, Grant/Award Number: FK123831 and NN125601; Hungarian Brain Research Program, Grant/Award Number: KTIA_NAP_13-2-2014-0014; Ministry of Human Capacities, Hungary, Grant/Award Number: 20391-3/2018/FEKUSTRAT; Marie Skłodowska-Curie Actions, Grant/Award Number: H2020-MSCA-ITN-2016-722053; Ester Floridia Neuroscience Research Foundation; Magor L. Lőrincz is a grantte of the János Bolyai Fellowship.
Uncontrolled Keywords: Childhood absence epilepsy,cortex,lh current,thalamocortical neurons,thalamus
Full Text Link:
Related URLs: https://onlinel ... .1111/epi.16926 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2021-07-01
Published Online Date: 2021-05-20
Accepted Date: 2021-04-27
Authors: Iacone, Yasmine
Morais, Tatiana P.
David, François
Delicata, Francis (ORCID Profile 0000-0002-5339-5275)
Sandle, Joanna
Raffai, Timea
Parri, Harri Rheinallt (ORCID Profile 0000-0002-1412-2688)
Weisser, Johan Juhl
Bundgaard, Christoffer
Klewe, Ib Vestergaard
Tamás, Gábor
Thomsen, Morten Skøtt
Crunelli, Vincenzo
Lőrincz, Magor L.

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