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The following is a summary of “Elevated peripheral glutamate and upregulated expression of NMDA receptor NR1 subunit in insomnia disorder,” published in the September 2024 issue of Psychiatry by Lin et al.

Researchers conducted a retrospective study that looked at how certain substances like serum glutamate (Glu), glutamine (Gln), and glutamic acid dehydrogenase (GAD) behave in the blood of people with insomnia disorder (ID). It also focused on a specific receptor subunit, N-methyl-D-aspartate receptor (NMDAR) NR1. 

They studied 30 patients with ID and 30 healthy controls, collecting demographic data and sleep quality scores using the Pittsburgh Sleep Quality Index. Depression and anxiety were measured with the Hamilton Depression Scale-17. Glu, Gln, and GAD levels were assessed by Enzyme-linked immunosorbent assay (ELISA), and NMDAR NR1 mRNA expression was analyzed via real-time PCR.

The results showed that patients with ID had significantly higher serum Glu levels and NMDAR NR1 mRNA expression than healthy controls. No differences were seen in Gln or GAD. The receiver operating characteristics (ROC) analysis indicated that NMDAR NR1 mRNA could distinguish patients with ID (AUC: 0.758; sensitivity: 73.3%; specificity: 76.7%). NMDAR NR1 mRNA levels negatively correlated with age, illness duration, and age of first onset but positively correlated with daytime dysfunction.

Investigators concluded that glutamatergic neurotransmission is abnormal in patients with ID, and NMDAR NR1 mRNA may be a potential biomarker. More extensive studies are needed to confirm these findings and better understand the underlying mechanisms and biomarker reliability.

Source: frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2024.1436024/abstract