Acute TrkB inhibition rescues phenobarbital‐resistant seizures in a mouse model of neonatal ischemia

SK Kang, MV Johnston… - European Journal of …, 2015 - Wiley Online Library
European Journal of Neuroscience, 2015Wiley Online Library
Neonatal seizures are commonly associated with hypoxic–ischemic encephalopathy.
Phenobarbital (PB) resistance is common and poses a serious challenge in clinical
management. Using a newly characterized neonatal mouse model of ischemic seizures, this
study investigated a novel strategy for rescuing PB resistance. A small‐molecule TrkB
antagonist, ANA 12, used to selectively and transiently block post‐ischemic BDNF‐TrkB
signaling in vivo, determined whether rescuing TrkB‐mediated post‐ischemic degradation of …
Abstract
Neonatal seizures are commonly associated with hypoxic–ischemic encephalopathy. Phenobarbital (PB) resistance is common and poses a serious challenge in clinical management. Using a newly characterized neonatal mouse model of ischemic seizures, this study investigated a novel strategy for rescuing PB resistance. A small‐molecule TrkB antagonist, ANA12, used to selectively and transiently block post‐ischemic BDNF‐TrkB signaling in vivo, determined whether rescuing TrkB‐mediated post‐ischemic degradation of the K+–Cl co‐transporter (KCC2) rescued PB‐resistant seizures. The anti‐seizure efficacy of ANA12 + PB was quantified by (i) electrographic seizure burden using acute continuous video‐electroencephalograms and (ii) post‐treatment expression levels of KCC2 and NKCC1 using Western blot analysis in postnatal day (P)7 and P10 CD1 pups with unilateral carotid ligation. ANA12 significantly rescued PB‐resistant seizures at P7 and improved PB efficacy at P10. A single dose of ANA12 + PB prevented the post‐ischemic degradation of KCC2 for up to 24 h. As anticipated, ANA12 by itself had no anti‐seizure properties and was unable to prevent KCC2 degradation at 24 h without follow‐on PB. This indicates that unsubdued seizures can independently lead to KCC2 degradation via non‐TrkB‐dependent pathways. This study, for the first time as a proof‐of‐concept, reports the potential therapeutic value of KCC2 modulation for the management of PB‐resistant seizures in neonates. Future investigations are required to establish the mechanistic link between ANA12 and the prevention of KCC2 degradation.
Wiley Online Library