GABA B receptors modulate Ca2+ but not G protein‐gated inwardly rectifying K+ channels in cerebrospinal‐fluid contacting neurones of mouse brainstem


  • Jurčić Nina
  • Er-Raoui Ghizlane
  • Airault Coraline
  • Trouslard Jérôme
  • Wanaverbecq Nicolas
  • Seddik Riad


  • Cerebrospinal fluid contacting neurone
  • GABAB receptor
  • GIRK channel
  • PKD2L1
  • Brainstem
  • Calcium channel
  • Patch-clamp
  • Synaptic transmission

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Medullo-spinal CSF contacting neurones (CSF-cNs) located around the central canal are conserved in all vertebrates and suggested to be a novel sensory system intrinsic to the CNS. CSF-cNs receive GABAergic inhibitory synaptic inputs involving ionotropic GABAA receptors, but the contribution of metabotropic GABAB receptors (GABAB -Rs) has not yet been studied. Here, we indicate that CSF-cNs express functional GABAB -Rs that inhibit postsynaptic calcium channels but fail to activate inhibitory potassium channel of the Kir3-type. We further show that GABAB -Rs localise presynaptically on GABAergic and glutamatergic synaptic inputs contacting CSF-cNs, where they inhibit the release of GABA and glutamate. Our data are the first to address the function of GABAB -Rs in CSF-cNs and show that on the presynaptic side they exert a classical synaptic modulation whereas at the postsynaptic level they have an atypical action by modulating calcium signalling without inducing potassium-dependent inhibition.

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