Obstructive sleep apnea is associated with low GABA and high glutamate in the insular cortex

Paul M. Macey, Manoj K. Sarma, Rajakumar Nagarajan, Ravi Aysola, Jerome M. Siegel, Ronald M. Harper, M. Albert Thomas

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)390-394
Number of pages5
JournalJournal of Sleep Research
Volume25
Issue number4
DOIs
StatePublished - Aug 1 2016
Externally publishedYes

Keywords

  • autonomic
  • intermittent excitoxicity hypoxia
  • neurotransmitter

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Behavioral Neuroscience

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