Dynamic balance of metabotropic inputs causes dorsal horn neurons to switch functional states.
Sensory relay structures in the spinal cord dorsal horn are now thought to be active processing structures that function before supraspinal sensory integration. Dorsal horn neurons directly receive nociceptive (pain) signals from the periphery, express a high degree of functional plasticity and are involved in long-term sensitization and chronic pain. We show here that deep dorsal horn neurons (DHNs) in Wistar rats can switch their intrinsic firing properties from tonic to plateau or endogenous bursting patterns, depending upon the balance of control by metabotropic glutamate (mGlu) and GABA(B) receptors. We further show that this modulation acts on at least one common target, the inwardly rectifying potassium channel (Kir3). Finally, we found that these firing modes correspond to specific functional states of information transfer in which dorsal horn neurons can faithfully transmit, greatly enhance or block the transfer of nociceptive information.
Derjean
Dominique
D
INSERM E0358, Physiopathologie des Réseaux Neuronaux Médullaires, Institut François Magendie, Université Bordeaux 2, Bordeaux, France.
Bertrand
Sandrine
S
Le Masson
Gwendal
G
Landry
Marc
M
Morisset
Valérie
V
Nagy
Frédéric
F
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D003198:Computer Simulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058788:GABA-B Receptor Antagonists; D066298:In Vitro Techniques; D008297:Male; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D018408:Patch-Clamp Techniques; D020671:Posterior Horn Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D051381:Rats; D017208:Rats, Wistar; D018080:Receptors, GABA-B / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018755:GABA Agonists; D018756:GABA Antagonists; D058788:GABA-B Receptor Antagonists; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D018080:Receptors, GABA-B; D018094:Receptors, Metabotropic Glutamate