The effect of Ting point (tendinomuscular meridians) electroacupuncture on thermal pain: a model for studying the neuronal mechanism of acupuncture analgesia.
OBJECTIVE
The aim of this study was to characterize the role of Ting points (TP) in acute pain management and its potential use in functional imaging studies by quantitatively assessing: (1) the change in peripheral thermal thresholds before and after the electroacupuncture (EA); and (2) the corresponding behavioral feedback of thermal pain stimulation and the de qi sensation of EA.


METHODS
The study design was prospective.


METHODS
Healthy subjects were recruited for the study at the University of California, San Diego Medical Center.


METHODS
Thirteen (13) healthy subjects were studied. Baseline thermal thresholds (cold and warm sensations and cold and hot pain) were measured at premarked testing sites along the medial aspects of bilateral lower extremities. Five (5) seconds of hot pain (HP) was delivered to the testing sites and the corresponding pain visual analog scale (VAS) scores were recorded. Thirty (30) seconds of EA was delivered via the SP1 and LR1 on the left lower extremities at 5 Hz via a 6-V square-wave stimulator.


METHODS
The VAS scores of the HP and de qi sensation (tingling) during the EA were recorded. The thermal thresholds and VAS scores for the HP and de qi were obtained immediately and both 30 and 60 minutes after the EA. Adaptation testing was also carried out to assess the change in thermal thresholds and the VAS scores of HP without EA.


RESULTS
The warm thresholds of bilateral medial calves significantly increased (p < 0.01) after 30 seconds of EA stimulation. The HP VAS score reduced significantly at the ipsilateral calf during EA in comparison to preacupuncture and postacupuncture (p < 0.01) measurements. No significant change in thermal thresholds was noted in the adaptation paradigm.


CONCLUSIONS
EA at the TP has an inhibitory effect on the C-fiber afferents. The analgesic benefit observed is most likely A-delta afferent mediated. Further correlation studies in functional imaging may provide defining data for the observed analgesic mechanism.
Leung
Albert
A
Department of Anesthesiology, University of California, San Diego, La Jolla, CA, USA. ayleung@ucsd.edu
Khadivi
Bahram
B
Duann
Jeng-Ren
JR
Cho
Z H
ZH
Yaksh
Tony
T
D015667:Acupuncture Analgesia / Q000379:methods; D000328:Adult; D016009:Chi-Square Distribution; D003080:Cold Temperature; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D016740:Meridians; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D059408:Pain Management; D010147:Pain Measurement; D017288:Pain Threshold; D012016:Reference Values; D013997:Time Factors