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TitleDifferential chloride homeostasis in the spinal dorsal horn locally shapes synaptic metaplasticity and modality-specific sensitization.
Publication TypeJournal Article
Year of Publication2020
AuthorsFerrini, Francesco, Jimena Perez-Sanchez, Samuel Ferland, Louis-Etienne Lorenzo, Antoine G. Godin, Isabel Plasencia-Fernández, Martin Cottet, Annie Castonguay, Feng Wang, Chiara Salio, Nicolas Doyon, Adalberto Merighi, and Yves De Koninck
JournalNat Commun
Date Published2020 08 07
KeywordsAnimals, Cells, Cultured, Central Nervous System Sensitization, Chlorides, Male, Membrane Glycoproteins, Mice, Models, Neurological, Neuronal Plasticity, Nociception, Optogenetics, Posterior Horn Cells, Primary Cell Culture, Protein-Tyrosine Kinases, Rats, Receptor, trkB, Symporters

GABA/glycine-mediated neuronal inhibition critically depends on intracellular chloride (Cl) concentration which is mainly regulated by the K-Cl co-transporter 2 (KCC2) in the adult central nervous system (CNS). KCC2 heterogeneity thus affects information processing across CNS areas. Here, we uncover a gradient in Cl extrusion capacity across the superficial dorsal horn (SDH) of the spinal cord (laminae I-II: LI-LII), which remains concealed under low Cl load. Under high Cl load or heightened synaptic drive, lower Cl extrusion is unveiled in LI, as expected from the gradient in KCC2 expression found across the SDH. Blocking TrkB receptors increases KCC2 in LI, pointing to differential constitutive TrkB activation across laminae. Higher Cl lability in LI results in rapidly collapsing inhibition, and a form of activity-dependent synaptic plasticity expressed as a continuous facilitation of excitatory responses. The higher metaplasticity in LI as compared to LII differentially affects sensitization to thermal and mechanical input. Thus, inconspicuous heterogeneity of Cl extrusion across laminae critically shapes plasticity for selective nociceptive modalities.

Alternate JournalNat Commun
PubMed ID32769979
PubMed Central IDPMC7414850
Grant ListMOP 12942 / / CIHR / Canada
FDN 159906 / / CIHR / Canada