Influence of tooth clench on the soleus H-reflex.
The Hoffmann (H) reflex is elicited by electrical stimulation of a mixed nerve and is used to measure the excitability of the spindle-motoneuron synapse. Recent investigations have indicated a positive correlation between increases in bite force and H-reflex facilitation. However, these investigations did not examine the H-reflex in detail or the possible role of periodontal mechanoreceptors (PMRs) in this facilitation. The current investigation was performed to determine whether PMRs play a role in H-reflex facilitation during tooth clench (TC). The H-reflex was elicited in the soleus muscle of human subjects while bite level was maintained at rest (0 N), 40 N, 80 N and maximal TC. The front teeth that contributed to the (40 N and 80 N) bite force were then locally anaesthetised (LA), and the protocol was repeated. The current data suggest that the effect of TC on the H-reflex amplitude in the human limb muscles is variable from one subject to the next. Statistical analysis has shown that the H-reflex was significantly smaller during the rest condition than during the 80 N bite (p<0.05) in both non-LA and LA conditions. Since LA did not alter the response, our results do not support that the PMRs play a major role in the facilitation of distal muscle activity.
Tuncer
Meltem
M
Hacettepe University, Faculty of Medicine, Department of Physiology, Sihhiye, Ankara 06100, Turkey.
Tucker
Kylie J
KJ
Türker
Kemal S
KS
D000328:Adult; D001732:Bite Force; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction; D008465:Mechanoreceptors / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010519:Periodontium / Q000502:physiology*; D011930:Reaction Time; D012026:Reflex, Stretch