Neuron
Volume 63, Issue 5, 10 September 2009, Pages 657-672
Journal home page for Neuron

Article
Differences in Cortical versus Subcortical GABAergic Signaling: A Candidate Mechanism of Electroclinical Uncoupling of Neonatal Seizures

https://doi.org/10.1016/j.neuron.2009.08.022Get rights and content
Under an Elsevier user license
open archive

Summary

Electroclinical uncoupling of neonatal seizures refers to electrographic seizure activity that is not clinically manifest. Uncoupling increases after treatment with Phenobarbital, which enhances the GABAA receptor (GABAAR) conductance. The effects of GABAAR activation depend on the intracellular Cl concentration ([Cl]i) that is determined by the inward Cl transporter NKCC1 and the outward Cl transporter KCC2. Differential maturation of Cl transport observed in cortical versus subcortical regions should alter the efficacy of GABA-mediated inhibition. In perinatal rat pups, most thalamic neurons maintained low [Cl]i and were inhibited by GABA. Phenobarbital suppressed thalamic seizure activity. Most neocortical neurons maintained higher [Cl]i, and were excited by GABAAR activation. Phenobarbital had insignificant anticonvulsant responses in the neocortex until NKCC1 was blocked. Regional differences in the ontogeny of Cl transport may thus explain why seizure activity in the cortex is not suppressed by anticonvulsants that block the transmission of seizure activity through subcortical networks.

HUMDISEASE
SYSNEURO
CHEMBIO

Cited by (0)

6

These authors contributed equally to this work