Entropy of Masseter Muscle Pain Sensitivity: A New Technique for Pain Assessment

2017 ◽  
Vol 31 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Eduardo Castrillon ◽  
Fernando Exposto ◽  
Hitoshi Sato ◽  
Tomohiro Tanosoto ◽  
Taro Arima ◽  
...  
Keyword(s):  
Pain Assessment ◽  
Muscle Pain ◽  
Masseter Muscle ◽  
Pain Sensitivity ◽  
New Technique ◽  
A New Technique

The pro-algesic effect of γ-aminobutyric acid (GABA) injection into the masseter muscle of healthy men and women

2019 ◽  
Vol 20 (1) ◽  
pp. 139-150
Author(s):  
Suzan Meijs ◽  
Shaojun Liao ◽  
Lars Arendt-Nielsen ◽  
Kelun Wang ◽  
Brian E. Cairns
Keyword(s):  
Muscle Pain ◽  
Masseter Muscle ◽  
Pain Sensitivity ◽  
Pressure Pain Threshold ◽  
Receptor Activation ◽  
Aminobutyric Acid ◽  
Saline Control ◽  
Masticatory Muscle ◽  
Healthy Men ◽  
Jaw Opening

AbstractBackground and aimsPreclinical studies have reported that activation of peripheral γ-aminobutyric acid A (GABAA) receptors may result in analgesia. The current study was conducted in young healthy men (n = 30) and women (n = 28) to determine whether injections of GABA into the masseter muscle reduce pain in a sex-related manner.MethodsThe effect of injection of GABA alone, or in combination with the non-inflammatory algogen glutamate, was assessed in two separate studies. Lorazepam, a positive allosteric modulator of the GABAA-receptor, was co-injected with GABA in both studies to explore the role of this receptor in muscle pain responses of healthy human volunteers. Masticatory muscle mechanical pain intensity was recorded on an electronic visual analogue scale (VAS) while muscle pain sensitivity was assessed by determining the pressure pain threshold (PPT), tolerance and maximal jaw opening (MJO) of the subjects prior to, and again after the various intramuscular injections.ResultsIntramuscular injection of GABA alone was reported to be significantly more painful, in a concentration related manner, than saline control injections, and this pain was further increased by co-injection of lorazepam with GABA. Co-injection of GABA with glutamate was found to significantly increase glutamate-evoked masseter muscle pain in men, but not in women. There was no effect of injections of either GABA alone, or GABA with glutamate, on PPT, tolerance or maximum jaw opening.ConclusionsInjection of GABA into the human masseter muscle appears to excite nociceptors to produce muscle pain without a longer term effect on mechanical pain sensitivity in the muscle. The findings suggest that GABA-mediated pain in humans is produced through peripheral GABAA receptor activation. The mechanism underlying the sex-related difference in the effect of GABA on glutamate-evoked muscle pain was speculated to be due to a methodological artifact.ImplicationsThis study was designed to detect analgesic rather than algesic effects of peripherally administered GABA, and as a result, the concentration of glutamate chosen for injection was close to the maximal pain response for healthy women, based on previously determined pain-concentration response relationships for glutamate. This may explain the finding of greater pain in men than women, when GABA and glutamate were co-injected. Overall, the findings suggest that activation of peripheral GABAA receptors in human masticatory muscle produces pain, possibly due to depolarization of the masticatory muscle afferent fibers.

Sinocutaneous fistula repair with a masseter muscle transposition flap combined with wound matrix and cancellous bone graft in a horse: A new technique

2019 ◽  
Vol 49 (4) ◽  
pp. 818-824
Author(s):  
Seiji Yoshimura ◽  
Spencer M. Barber ◽  
Michelle L. Tucker ◽  
José L. Bracamonte ◽  
Suzanne J. K. Mund ◽  
...  
Keyword(s):  
Bone Graft ◽  
Cancellous Bone ◽  
Masseter Muscle ◽  
New Technique ◽  
Cancellous Bone Graft ◽  
Fistula Repair ◽  
Muscle Transposition ◽  
Transposition Flap ◽  
Wound Matrix ◽  
A New Technique

A new technique for the mapping of oxygen tension on the brain surface

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S543-S543
Author(s):  
Satoshi Kimura ◽  
Keigo Matsumoto ◽  
Yoshio Imahori ◽  
Katsuyoshi Mineura ◽  
Toshiyuki Itoh
Keyword(s):  
Oxygen Tension ◽  
New Technique ◽  
Brain Surface ◽  
A New Technique ◽  
The Brain
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