Dharmadhikari, ShalmaliRomito, Laura M.Dzemidzic, MarioDydak, UlrikeXu, JunBodkin, Cynthia L.Manchanda, ShaliniByrd, Kenneth E.2016-03-012016-03-012015-07Dharmadhikari, S., Romito, L. M., Dzemidzic, M., Dydak, U., Xu, J., Bodkin, C. L., … Byrd, K. E. (2015). GABA and Glutamate Levels in Occlusal Splint-Wearing Males with Possible Bruxism. Archives of Oral Biology, 60(7), 1021–1029. http://doi.org/10.1016/j.archoralbio.2015.03.006https://hdl.handle.net/1805/8597Objective The inhibitory neurotransmitter γ-aminobutyric acid (GABA) plays an important role in the pathophysiology of anxiety behavioural disorders such as panic disorder and post-traumatic stress disorder and is also implicated in the manifestation of tooth-grinding and clenching behaviours generally known as bruxism. In order to test whether the stress-related behaviours of tooth-grinding and clenching share similar underlying mechanisms involving GABA and other metabolites as do anxiety-related behavioural disorders, we performed a Magnetic Resonance Spectroscopy (MRS) study for accurate, in vivo metabolite quantification in anxiety-related brain regions. Design MRS was performed in the right hippocampus and right thalamus involved in the hypothalamic−pituitary−adrenal axis system, together with a motor planning region (dorsal anterior cingulate cortex/pre-supplementary motor area) and right dorsolateral prefrontal cortex (DLPFC). Eight occlusal splint-wearing men (OCS) with possible tooth-grinding and clenching behaviours and nine male controls (CON) with no such behaviour were studied. Results Repeated-measures ANOVA showed significant Group × Region interaction for GABA+ (p = 0.001) and glutamate (Glu) (p = 0.031). Between-group post hoc ANOVA showed significantly lower levels of GABA+ (p = 0.003) and higher levels of Glu (p = 0.002) in DLPFC of OCS subjects. These GABA+ and Glu group differences remained significant (GABA+, p = 0.049; Glu, p = 0.039) after the inclusion of anxiety as a covariate. Additionally, GABA and Glu levels in the DLPFC of all subjects were negatively related (Pearson's r = −0.75, p = 0.003). Conclusions These findings indicate that the oral behaviours of tooth-grinding and clenching, generally known as bruxism, may be associated with disturbances in brain GABAergic and glutamatergic systems.en-USPublisher PolicyMRSBruxismAnxietyMetabolitesGABAPathophysiologyArticle