**3.4 Temporomandibular pain disorders**

Compared to the healthy controls, fibromyalgia patients had increased 5-HT in the masseter muscle (Ernberg et al., 1999). Compared to the healthy controls, myofascial temporomandibular disorder patients had significantly higher glutamate levels (Castrillon et al., 2010) (**Table 4**).

We identified two studies (**Table 2**) using the same material concerning patients with chronic WAD (Gerdle et al., 2008b; Gerdle et al., 2008c), and 5-HT and IL-6 were significantly higher in WAD than in HC. No differences were found in the concentrations of investigated metabolites, potassium, glutamate, BKN, or kallidin compared with healthy

Two studies investigated fibromyalgia patients (**Table 3**). In the larger study investigating the painful trapezius muscle of fibromyalgia patients, significantly higher interstitial concentrations of lactate and pyruvate were found compared to healthy controls (Gerdle et al., 2010). In the other study, the vastus lateralis muscle was investigated in eight patients with fibromyalgia and the authors reported no differences in concentrations of lactate compared to controls (McIver et al., 2006). It is unclear from this study if the vastus lateralis was habitually painful and/or painful at palpation (e.g., tender point examination).

Results

p-values)

ns.

Table 3. Studies of fibromyalgia. The results of the different substances are baseline data.

Compared to the healthy controls, fibromyalgia patients had increased 5-HT in the masseter muscle (Ernberg et al., 1999). Compared to the healthy controls, myofascial temporomandibular disorder patients had significantly higher glutamate levels (Castrillon

(Comparisons between patients and HC;

Lactate-trapezius: FM>HC; P=0.039 Pyruvate-trapezius: FM>HC; P=0.001 Glutamate-trapezius: Comments (Compensated for RR (Y/N) or low flow rate\* (NA or Y/N)

Compensated for

RR: N Low flow: Y

RR: N Low flow: N

Lactate-vastus: ns Compensated for

Moreover, no compensation for RR was done despite a relatively high flow rate.

Substances investigated Flow rate

Lactate Pyruvate Glutamate

0.3µl/min

Lactate

2µl/min

\*Low flow rate associated with 100% relative recovery was defined as 0.3µl/min

**3.2 Chronic WAD** 

**3.3 Fibromyalgia** 

Study Condition

 Number of Subjects, % women (W) Muscles

Fibromyalgia (FM; n=19), 100% W HC (n=19), 100% W

Trapezius

Fibromyalgia (FM; n=8), 100%W HC (n=8), 100% W Vastus lateralis

Healthy controls are abbreviated as HC.

**3.4 Temporomandibular pain disorders** 

et al., 2010) (**Table 4**).

controls.

Gerdle et al. (Gerdle et al., 2010)

McIver et al (McIver et al., 2006)


\*Low flow rate associated with 100% relative recovery was defined as 0.3µl/min.

Table 4. Studies of temporomandibular pain disorders. The results of the different substances are baseline data. Healthy controls are abbreviated as HC.
