Obstructive sleep apnea is associated with low GABA and high glutamate in the insular cortex
Version of Record online: 4 FEB 2016
© 2016 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.
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Journal of Sleep Research
How to Cite
Macey, P. M., Sarma, M. K., Nagarajan, R., Aysola, R., Siegel, J. M., Harper, R. M. and Thomas, M. A. (2016), Obstructive sleep apnea is associated with low GABA and high glutamate in the insular cortex. Journal of Sleep Research. doi: 10.1111/jsr.12392
- Version of Record online: 4 FEB 2016
- Manuscript Accepted: 28 DEC 2015
- Manuscript Revised: 24 DEC 2015
- Manuscript Received: 29 SEP 2015
- . Grant Number: NIH-NR-013693
- intermittent excitoxicity hypoxia;
The insular cortex is injured in obstructive sleep apnea (OSA) and responds inappropriately to autonomic challenges, suggesting neural reorganization. The objective of this study was to assess whether the neural changes might result from γ-aminobutyric acid (GABA) and glutamate alterations. We studied 14 OSA patients [mean age ± standard deviation (SD): 47.5 ± 10.5 years; nine male; apnea–hypopnea index (AHI): 29.5 ± 15.6 events h−1] and 22 healthy participants (47.5 ± 10.1 years; 11 male), using magnetic resonance spectroscopy to detect GABA and glutamate levels in insular cortices. We localized the cortices with anatomical scans, and measured neurochemical levels from anterior to mid-regions. Left and right anterior insular cortices showed lower GABA and higher glutamate in OSA versus healthy subjects [GABA left: OSA n = 6: 0.36 ± 0.10 (mean ± SD), healthy n = 5: 0.62 ± 0.18; P < 0.05), right: OSA n = 11: 0.27 ± 0.09, healthy n = 14: 0.45 ± 0.16; P < 0.05; glutamate left: OSA n = 6: 1.61 ± 0.32, healthy n = 8: 0.94 ± 0.34; P < 0.05, right: OSA n = 14: 1.26 ± 0.28, healthy n = 19: 1.02 ± 0.28; P < 0.05]. GABA and glutamate levels were correlated only within the healthy group in the left insula (r: −0.9, P < 0.05). The altered anterior insular levels of GABA and glutamate may modify integration and projections to autonomic areas, contributing to the impaired cardiovascular regulation in OSA.