title: Restoration of post-activation depression of the H-reflex by treadmill exercise in aged rats.
abstract: The purpose of this study was to evaluate the effects of aging and chronic physical activity on the postactivation depression of the Hoffman reflex (H-reflex). The maximal amplitude H wave/maximal amplitude M wave ratio was measured, and the rate-sensitive depression of the H-reflex was assessed. Measurements were performed on sedentary rats aged of 3, 6, 12, and 20 months and on animals aged of 12 and 20 months performing an incremental treadmill exercise protocol during the last eight weeks preceding the recordings. At the end of the experiment, the muscle mass and/or body mass ratio was calculated. Results indicated that the H-reflex depression of the tibialis anterior and soleus muscles were present until age of 6 and 12 months, respectively. For the tibialis anterior muscle, results also pointed out a decrease in the relative muscle mass with age and that the exercise allowed to restore the rate-sensitive depression of the H-reflex and to increase the relative muscle mass in comparison with sedentary animals. These findings clearly demonstrate that neural alteration of the spinal cord is prevented by activity in aged rats.
authors.affiliation: Aix-Marseille Université (AMU) and Centre National de la Recherche Scientifique (CNRS) UMR 7287 « Institut des Sciences du Mouvement: Etienne-Jules MAREY » (ISM-EJM) Equipe « Plasticité des Systèmes Nerveux et Musculaire » (PSNM) Parc Scientifique et Technologique de Luminy Faculté des Sciences du Sport de Marseille CC910 - 163 Avenue de Luminy F-13288 Marseille cedex 09, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Caron
authors.affiliation: Aix-Marseille Université (AMU) and Centre National de la Recherche Scientifique (CNRS) UMR 7287 « Institut des Sciences du Mouvement: Etienne-Jules MAREY » (ISM-EJM) Equipe « Plasticité des Systèmes Nerveux et Musculaire » (PSNM) Parc Scientifique et Technologique de Luminy Faculté des Sciences du Sport de Marseille CC910 - 163 Avenue de Luminy F-13288 Marseille cedex 09, France.
authors.forename: Tanguy
authors.initials: T
authors.lastname: Marqueste
authors.affiliation: Aix-Marseille Université (AMU) and Centre National de la Recherche Scientifique (CNRS) UMR 7287 « Institut des Sciences du Mouvement: Etienne-Jules MAREY » (ISM-EJM) Equipe « Plasticité des Systèmes Nerveux et Musculaire » (PSNM) Parc Scientifique et Technologique de Luminy Faculté des Sciences du Sport de Marseille CC910 - 163 Avenue de Luminy F-13288 Marseille cedex 09, France. Electronic address: patrick.decherchi@univ-amu.fr.
authors.forename: Patrick
authors.initials: P
authors.lastname: Decherchi
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D001823:Body Composition; D005080:Exercise Test; D006181:H-Reflex / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000503:physiopathology
keywords: Aging; Extensor; Flexor; H-reflex; Postactivation depression