T. Marqueste and P. Decherchi contributed equally to this work.
Mechano- and metabosensitive alterations after injection of botulinum toxin into gastrocnemius muscle
Article first published online: 25 FEB 2014
Copyright © 2014 Wiley Periodicals, Inc.
Journal of Neuroscience Research
Volume 92, Issue 7, pages 904–914, July 2014
How to Cite
Caron, G., Rouzi, T., Grelot, L., Magalon, G., Marqueste, T. and Decherchi, P. (2014), Mechano- and metabosensitive alterations after injection of botulinum toxin into gastrocnemius muscle. J. Neurosci. Res., 92: 904–914. doi: 10.1002/jnr.23370
- Issue published online: 13 MAY 2014
- Article first published online: 25 FEB 2014
- Manuscript Accepted: 16 JAN 2014
- Manuscript Revised: 14 JAN 2014
- Manuscript Received: 28 AUG 2013
- Aix-Marseille Université (AMU)
- Centre National de la Recherche Scientifique (CNRS)
- Assistance Publique—Hôpitaux de Marseille (AP-HM)
- muscular afferents;
- Clostridium botulinum;
This study was designed to investigate effects of motor denervation by Clostridium botulinum toxin serotype A (BoNT/A) on the afferent activity of fibers originating from the gastrocnemius muscle of rats. Animals were randomized in two groups, 1) untreated animals acting as control and 2) treated animals in which the toxin was injected in the left muscle. Locomotor activity was evaluated once per day during 12 days with a test based on footprint measurements of walking rats (sciatic functional index). At the end of the functional assessment period, electrophysiological tests were used to measure muscle properties, metabosensitive afferent fiber responses to chemical (KCl and lactic acid) injections, electrically induced fatigue (EIF), and mechanosensitive responses to tendon vibrations. Additionally, ventilatory response was recorded during repetitive muscle contractions. Then, rats were sacrificed, and the BoNT/A-injected muscles were weighed. Twelve days postinjection we observed a complete motor denervation associated with a significant muscle atrophy and loss of force to direct muscle stimulation. In the BoNT/A group, the metabosensitive responses to KCl injections were unaltered. However, we observed alterations in responses to EIF and to 1 mM of lactic acid (which induces the greatest activation). The ventilatory adjustments during repetitive muscle activation were abolished, and the mechanosensitive fiber responses to tendon vibrations were reduced. These results indicate that BoNT/A alters the sensorimotor loop and may induce insufficient motor and physiological adjustments in patients in whom a motor denervation with BoNT/A was performed. © 2014 Wiley Periodicals, Inc.