Disease relevance of Masseter Muscle

• We have previously reported that the level of 5-HT in the masseter muscle is increased in patients with fibromyalgia as compared with healthy subjects and that high intramuscular level of 5-HT is associated with muscle pain [1].
• The aim of this study was to investigate the effect of injection of serotonin (5-HT) into the masseter muscle on pain and allodynia/hyperalgesia [2].
• BACKGROUND: The agonist actions of succinylcholine (SCh) have recently come under study because of their involvement in the clinical problem of masseter muscle rigidity, and their possible involvement in malignant hyperthermia [3].
• Preparations from MH-negative patients with a history of masseter muscle rigidity were rendered sensitive to halothane (contractures of 1.17 +/- 0.30 g; n = 4) when SCh was present [4].
• Isolated masseter muscle spasm and increased creatine kinase without malignant hyperthermia susceptibility or other myopathies [5].

Psychiatry related information on Masseter Muscle

• The effects of an occlusal splint on the electromyographic activities of the temporal and masseter muscles during maximal clenching in patients with a habit of nocturnal bruxism and signs and symptoms of craniomandibular disorders [6].

High impact information on Masseter Muscle

• Denervation of the masseter muscle of rats by unilateral superior cervical ganglionectomy markedly diminished tissue norepinephrine and epinephrine levels but had no effect on masseter PNMT or NMT levels [7].
• Our results thus confirm previous histochemical data and demonstrate that the masseter muscle displays a pattern of myosin and tropomyosin isoform transitions different to that previously described in trunk and limb muscles [8].
• Masseter muscle glucose uptake was not significantly altered over a wide range of ascorbate or dehydroascorbate concentrations in the injectate [9].
• Local injection of CGRP antagonist directly into the masseter muscle prior to CFA produced similar, but less pronounced, effects [10].
• The present results suggest that injection of 1.0M glutamate into the masseter muscle may provide a useful experimental method to test sensitization and efficacy of peripheral EAA receptor antagonists in human subjects [11].

Chemical compound and disease context of Masseter Muscle

• In conclusion, our results show that 5-HT injected into the masseter muscle of healthy female subjects elicits pain and allodynia/hyperalgesia, while no such responses occur in patients with fibromyalgia [2].
• BACKGROUND: Succinylcholine-induced masseter muscle rigidity (MMR) is a potentially life-threatening complication of anesthesia and is closely correlated with the heterogeneous disorder malignant hyperthermia (MH) susceptibility [12].
• The purpose of the present study was to determine the extent to which transforming growth factor betas (TGFbetas), fibroblast growth factors (FGFs), hepatocyte growth factor (HGF), and platelet-derived growth factors (PDGFs) are involved in the hypertrophy of rat masseter muscle induced by clenbuterol [13].
• Injecting the drug into the masseter muscles or intraperitoneally did not render the snout anaptic or abolish retrieval, results indicating that the effect of intramystacial lidocaine treatment could not be attributed to systemic toxicity or to the drug's spreading from the mystacial pads to affect the nearby masseter muscles [14].
• Capsaicin-induced muscle hyperalgesia in the exercised and non-exercised human masseter muscle [15].

Biological context of Masseter Muscle

• These results are consistent with the hypothesis that androgen-induced differences in rabbit masseter muscle fiber phenotype are a reflection of differences in motoneuron firing rate [16].
• Infusion of leucine increased (P < 0.05) phosphorylation of eukaryotic initiation factor (eIF)4E-binding protein-1 and increased (P < 0.05) the amount and phosphorylation of eIF4G associated with eIF4E in longissimus dorsi and masseter muscles and in both ventricular walls [17].
• Effect of ibuprofen on isometric contractions and associated pain of the human masseter muscle [18].
• From these results, we suggest that measurement of the onset time of muscle relaxation at the masseter muscle appears to be a better predictor of good intubating conditions than measurements made using the adductor pollicis muscle after administration of rocuronium [19].
• Quantitative electromyography (EMG) was used to study, in eleven volunteers with complete, natural dentitions, the effects of an experimental intercuspal occlusal interference on the pattern of activity of the anterior temporal and masseter muscles during mastication [20].

Anatomical context of Masseter Muscle

• Moreover, local administration of ketanserin (0.1 mg) or propranolol (0.1 mg) into masseter muscle did not inhibit nocifensive orofacial behavior in rats without TMJ inflammation [21].
• We used SR microsomes of canine masseter muscle as a model system in which to explore the effect of oxidation by determining oxalate-supported Ca++ uptake, Ca++, Mg++-adenosine triphosphatase (Ca++-ATPase) activity and Ca++ permeability of the SR vesicles [22].
• In the absence of dantrolene, occlusal alteration leads to microvessel constriction, morphologic damage of masseter muscle fibers and blood capillaries, and elevation of tissue Ca2+ content [23].
• The results show that occlusal dysfunction leads to microvessel constriction and clear-cut morphologic damage of muscular fibers and blood capillary endothelium, as well as to elevation of tissue calcium content, in the ipsilateral masseter muscle [24].
• These results suggest that the increase in caffeine sensitivity of masseter muscle reflects the presence of a low reactivity threshold of the sarcoplasmic reticulum [25].

Associations of Masseter Muscle with chemical compounds

• 5-HT in one of three randomized concentrations (10(-3), 10(-5), 10(-7) M) or isotonic saline was then injected into either of the two masseter muscles in a double-blind manner [2].
• In this open, uncontrolled trial, 20 patients with upper trapezius muscle trigger point pain and ipsilateral masseter muscle pain received a single trigger point injection of 2% lidocaine solution (without epinephrine) in the upper trapezius muscle [26].
• In random order 5% hypertonic or 0.9% isotonic saline was infused into the left masseter muscle for 15 min [27].
• In ten healthy subjects we recorded the subjective ratings of the perioral laser stimulation and the trigeminal LEPs and LSP before, during and after homotopic experimental tonic muscle (infusion of hypertonic saline into the masseter muscle) and tonic skin pain (topical application of capsaicin to the cheek) [28].
• First, we demonstrated that different algesic chemicals, mustard oil (20%), formalin (3%) or hypertonic saline (5%) injected in the mid-region of the masseter muscle effectively elicited the hindpaw shaking behavior [29].

Gene context of Masseter Muscle

• Masseter muscle activities of BDNF-deficient mice exhibited smaller values than those of wild-type mice [30].
• Myosin heavy chain isoforms of the murine masseter muscle during pre- and post-natal development [31].
• Masticatory function and properties of masseter muscle fibers in microphthalmic (mi/mi) mice during postnatal development [32].
• Abundant expression of myosin heavy-chain IIB RNA in a subset of human masseter muscle fibres [33].
• Thus, IGF-I, IGF-II, IGFR2, and IGFBP5 seem to play a role in the atrophy of mouse masseter muscle in response to the change from a hard to a soft diet in an autocrine and/or paracrine manner [34].

Analytical, diagnostic and therapeutic context of Masseter Muscle

• BACKGROUND: Animal experiments revealed that succinylcholine produced masseter muscle rigidity and activated myotonic discharges despite neuromuscular blockade with a nondepolarizing blocker [35].
• Electroencephalograms (EEGs) were recorded from 11 electrodes placed over the scalp (F3, Fz, F4, T3, C3, Cz, C4, T4, P3, Pz, and P4), according to the International 10-20 System, and electromyograms (EMGs) were obtained from surface electrodes over the masseter muscle and the anterior belly of the digastric muscle [36].
• 2. We measured the mRNA expression levels for TGFbetas, FGFs, HGF, and PDGFs in rat masseter muscle hypertrophied by oral administration of clenbuterol for 3 weeks and determined correlations between the weight of masseter muscle and mRNA expression levels by regression analysis [13].
• Intraperitoneal injection of a small amount of interleukin-1 (IL-1) (from 1 to 10 microg/kg) produced a similar elevation of HDC activity in the masseter muscle [37].
• Electrical stimulation of the mental nerve evokes two suppression periods SP1 and SP2 in masseter muscle activity bilaterally [38].

References