Kissane, RWP, Ghaffari-Rafi, A, Tickle, PG orcid.org/0000-0003-0389-3580 et al. (4 more authors) (2022) C-bouton components on rat extensor digitorum longus motoneurons are resistant to chronic functional overload. Journal of Anatomy, 241 (5). pp. 1157-1168. ISSN 0021-8782
Abstract
Mammalian motor systems adapt to the demands of their environment. For example, muscle fibre types change in response to increased load or endurance demands. However, for adaptations to be effective, motoneurons must adapt such that their properties match those of the innervated muscle fibres. We used a rat model of chronic functional overload to assess adaptations to both motoneuron size and a key modulatory synapse responsible for amplification of motor output, C-boutons. Overload of extensor digitorum longus (EDL) muscles was induced by removal of their synergists, tibialis anterior muscles. Following 21 days survival, EDL muscles showed an increase in fatigue resistance and a decrease in force output, indicating a shift to a slower phenotype. These changes were reflected by a decrease in motoneuron size. However, C-bouton complexes remained largely unaffected by overload. The C-boutons themselves, quantified by expression of vesicular acetylcholine transporter, were similar in size and density in the control and overload conditions. Expression of the post-synaptic voltage-gated potassium channel (KV2.1) was also unchanged. Small conductance calcium-activated potassium channels (SK3) were expressed in most EDL motoneurons, despite this being an almost exclusively fast motor pool. Overload induced a decrease in the proportion of SK3+ cells, however, there was no change in density or size of clusters. We propose that reductions in motoneuron size may promote early recruitment of EDL motoneurons, but that C-bouton plasticity is not necessary to increase the force output required in response to muscle overload.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2021 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | C-bouton; Kv2.1; overload; plasticity; SK3; spinal cord |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) |
Funding Information: | Funder Grant number International Foundation for Research in Paraplegia P153 |
Depositing User: | Symplectic Publications |
Date Deposited: | 14 May 2021 09:22 |
Last Modified: | 03 Jan 2023 14:25 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1111/joa.13439 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:173961 |