Shalmali Dharmadhikari1, Laura M Romito2, Mario Dzemidzic3, Ulrike Dydak4, Jun Xu5, Cynthia L Bodkin6, Shalini Manchanda7, Kenneth E Byrd8. 1. Purdue University School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA; Department of Radiology, Indiana University School of Medicine, 550 North University Boulevard Room 0663, Indianapolis, IN 46202, USA. Electronic address: shdharma@iupui.edu. 2. Department of Oral Biology, Indiana University School of Dentistry, 1121 West Michigan Street, Indianapolis, IN 46202, USA. Electronic address: lromitoc@iu.edu. 3. Department of Neurology, Indiana University School of Medicine, Goodman Hall, Suite 4700, 355 West 16th Street, Indianapolis, IN 46202, USA; Department of Radiology, Indiana University School of Medicine, 550 North University Boulevard Room 0663, Indianapolis, IN 46202, USA. Electronic address: mdzemidz@iupui.edu. 4. Purdue University School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA; Department of Radiology, Indiana University School of Medicine, 550 North University Boulevard Room 0663, Indianapolis, IN 46202, USA. Electronic address: udydak@iupui.edu. 5. Department of Radiology, Indiana University School of Medicine, 550 North University Boulevard Room 0663, Indianapolis, IN 46202, USA. Electronic address: jx3@iupui.edu. 6. Department of Neurology, Indiana University School of Medicine, Goodman Hall, Suite 4700, 355 West 16th Street, Indianapolis, IN 46202, USA; Indiana University Health Sleep Disorders Center, Indiana University School of Medicine, 714 N. Senate Avenue, Suite 120, Indianapolis, IN 46202, USA. Electronic address: cbodkin@iupui.edu. 7. Department of Neurology, Indiana University School of Medicine, Goodman Hall, Suite 4700, 355 West 16th Street, Indianapolis, IN 46202, USA; Indiana University Health Sleep Disorders Center, Indiana University School of Medicine, 714 N. Senate Avenue, Suite 120, Indianapolis, IN 46202, USA. Electronic address: smanchan@iu.edu. 8. Department of Oral Biology, Indiana University School of Dentistry, 1121 West Michigan Street, Indianapolis, IN 46202, USA; Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS-5035, Indianapolis, IN 46202, USA. Electronic address: kbyrd@iupui.edu.
Abstract
OBJECTIVE: 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.
OBJECTIVE: 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.
Authors: Soohyun Cho; Arron W S Metcalfe; Christina B Young; Srikanth Ryali; David C Geary; Vinod Menon Journal: J Cogn Neurosci Date: 2012-05-23 Impact factor: 3.225
Authors: Ruth A Lanius; Peter C Williamson; James Hopper; Maria Densmore; Kristine Boksman; Madhulika A Gupta; Robert W J Neufeld; Joseph S Gati; Ravi S Menon Journal: Biol Psychiatry Date: 2003-02-01 Impact factor: 13.382