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

Iacone, Yasmine, Morais, Tatiana P., David, François, Delicata, Francis, Sandle, Joanna, Raffai, Timea, Parri, Harri Rheinallt, Weisser, Johan Juhl, Bundgaard, Christoffer, Klewe, Ib Vestergaard, Tamás, Gábor, Thomsen, Morten Skøtt, Crunelli, Vincenzo ORCID: https://orcid.org/0000-0001-7154-9752 and Lorincz, Magor L. 2021. Systemic administration of ivabradine, a hyperpolarization-activated cyclic nucleotide-gated channel inhibitor, blocks spontaneous absence seizures. Epilepsia 62 (7) , pp. 1729-1743. 10.1111/epi.16926

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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.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences
Additional Information:	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
Publisher:	Wiley
ISSN:	0013-9580
Date of First Compliant Deposit:	29 July 2021
Date of Acceptance:	27 April 2021
Last Modified:	07 May 2023 01:25
URI:	https://orca.cardiff.ac.uk/id/eprint/143023

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