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 language | English |
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Pages (from-to) | 2448-2453 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 104 |
Issue number | 7 |
DOIs | |
Publication status | Published - 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