Temperature affects maximum H-reflex amplitude but not homosynaptic postactivation depression

Racinais, Sebastien and Cresswell, Andrew G. (2013) Temperature affects maximum H-reflex amplitude but not homosynaptic postactivation depression. Physiological Reports, 1 2: e00019.1-e000197. doi:10.1002/phy2.19


Author Racinais, Sebastien
Cresswell, Andrew G.
Title Temperature affects maximum H-reflex amplitude but not homosynaptic postactivation depression
Journal name Physiological Reports   Check publisher's open access policy
ISSN 2051-817X
Publication date 2013
Year available 2013
Sub-type Article (original research)
DOI 10.1002/phy2.19
Open Access Status DOI
Volume 1
Issue 2
Start page e00019.1
End page e000197
Total pages 8
Place of publication Oxford, United Kingdom
Publisher John Wiley and Sons Ltd.
Collection year 2013
Language eng
Formatted abstract
This study aimed to determinate the effect of hyperthermia on transmission efficacy of the Ia-afferent spinal pathway. Recruitment curves of the Hoffman reflex (H-reflex) and compound motor potential (M-wave) along with homosynaptic postactivation depression (HPAD) recovery curves were obtained in 14 volunteers in two controlled ambient temperatures that resulted in significantly different core temperatures (CON, core temperature 37.3°C; and HOT, core temperature 39.0°C). Electromyographic responses were obtained from the soleus (SOL) and medial gastrocnemius (MG) muscles following electrical stimulation of the tibial nerve at varying intensities and paired pulse frequencies (0.07-10 Hz). Results showed that maximal amplitude of the H-reflex was reached for a similar intensity of stimulation in CON and HOT (both muscles P > 0.47), with a similar associated M-wave (both muscles P > 0.69) but was significantly decreased in HOT as compared to CON (all P < 0.05), whether expressed in absolute terms (-50% in SOL, -32% in MG) or when normalized to the maximum M-wave (-23% in SOL, -32% in MG). The HPAD recovery curve was not affected by the elevated core temperature (both muscles P > 0.23). Taken together, these results suggest that hyperthermia can alter neuromuscular transmission across the neuromuscular junction and/or muscle membrane as well as transmission efficacy of the Ia-afferent pathway, albeit the latter not via an increase in HPAD.
Keyword Exercise
Hyperthermia
Muscle
Neuromuscular function
Spinal reflex
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Human Movement and Nutrition Sciences Publications
 
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Created: Mon, 03 Nov 2014, 09:21:38 EST by Sandrine Ducrot on behalf of School of Human Movement and Nutrition Sciences