Enhancing GABAergic Tonic Inhibition Reduces Seizure-Like Activity in the Neonatal Mouse Hippocampus and Neocortex.
J Neurosci
; 44(7)2024 Feb 14.
Article
em En
| MEDLINE
| ID: mdl-38176909
ABSTRACT
Approximately one-third of neonatal seizures do not respond to first-line anticonvulsants, including phenobarbital, which enhances phasic inhibition. Whether enhancing tonic inhibition decreases seizure-like activity in the neonate when GABA is mainly depolarizing at this age is unknown. We evaluated if increasing tonic inhibition using THIP [4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol, gaboxadol], a δ-subunit-selective GABAA receptor agonist, decreases seizure-like activity in neonatal C57BL/6J mice (postnatal day P5-8, both sexes) using acute brain slices. Whole-cell patch-clamp recordings showed that THIP enhanced GABAergic tonic inhibitory conductances in layer V neocortical and CA1 pyramidal neurons and increased their rheobase without altering sEPSC characteristics. Two-photon calcium imaging demonstrated that enhancing the activity of extrasynaptic GABAARs decreased neuronal firing in both brain regions. In the 4-aminopyridine and the low-Mg2+ model of pharmacoresistant seizures, THIP reduced epileptiform activity in the neocortex and CA1 hippocampal region of neonatal and adult brain slices in a dose-dependent manner. We conclude that neocortical layer V and CA1 pyramidal neurons have tonic inhibitory conductances, and when enhanced, they reduce neuronal firing and decrease seizure-like activity. Therefore, augmenting tonic inhibition could be a viable approach for treating neonatal seizures.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores de GABA-A
/
Neocórtex
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Neurosci
Ano de publicação:
2024
Tipo de documento:
Article