Spinal cholinergic interneurons regulate the excitability of motoneurons during locomotion

Gareth Brian Miles, R Hartley, A J Todd, R M Brownstone

Research output: Contribution to journalArticlepeer-review

245 Citations (Scopus)

Abstract

To effect movement, motoneurons must respond appropriately to motor commands. Their responsiveness to these inputs, or excitability, is regulated by neuromodulators. Possible sources of modulation include the abundant cholinergic "C boutons" that surround motoneuron somata. In the present study, recordings from motoneurons in spinal cord slices demonstrated that cholinergic activation of m(2)-type muscarinic receptors increases excitability by reducing the action potential afterhyperpolarization. Analyses of isolated spinal cord preparations in which fictive locomotion was elicited demonstrated that endogenous cholinergic inputs increase motoneuron excitability during locomotion. Anatomical data indicate that C boutons originate from a discrete group of interneurons lateral to the central canal, the medial partition neurons. These results highlight a unique component of spinal motor networks that is critical in ensuring that sufficient output is generated by motoneurons to drive motor behavior.

Original languageEnglish
Pages (from-to)2448-2453
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number7
DOIs
Publication statusPublished - 13 Feb 2007

Keywords

  • afterhyperpolarization
  • C bouton
  • central pattern generator
  • muscarinic receptors
  • spinal cord
  • MUSCARINIC RECEPTOR SUBTYPES
  • DIFFERENTIAL EXPRESSION
  • ACETYLCHOLINE-RECEPTOR
  • LUMBAR MOTONEURONS
  • MOTOR-NEURONS
  • C-TERMINALS
  • IN-VITRO
  • CORD
  • RAT
  • MODULATION

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