Impairment of GABA inhibition in insomnia disorders: Evidence from the peripheral blood system

AimTo explore the change characteristics and related factors of various indexes of GABAergic system in peripheral blood of patients with insomnia disorder. MethodsIn this study, a total of 30 patients who met the DSM-5 diagnostic criteria for insomnia disorder and 30 normal controls were included. All subjects had a structured clinical interview with the Brief International Neuropsychiatric Disorder Interview, and PSQI was used to evaluate the sleep status of the subjects. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum gamma-aminobutyric acid (GABA), and RT-PCR was used to detect GABA(A) receptor alpha 1 and alpha 2 subunit mRNA. All data were statistically analyzed using SPSS 23.0. ResultsCompared with the normal control group, the mRNA levels of GABA(A) receptor alpha 1 and alpha 2 subunits in the insomnia disorder group were significantly lower, but there was no significant difference in the serum GABA levels between the two groups. And in the insomnia disorder group, there was no significant correlation between the GABA levels and the mRNA expression levels of alpha 1 and alpha 2 subunits of GABA(A) receptors. Although no significant correlation was found between PSQI and serum levels of these two subunit mRNAs, its component factors sleep quality and sleep time were negatively correlated with GABA(A) receptor alpha 1 subunit mRNA levels, and daytime function was inversely correlated with GABA(A) receptor alpha 2 subunit mRNA levels. ConclusionThe inhibitory function of serum GABA in patients with insomnia may be impaired, and the decreased expression levels of GABA(A) receptor alpha 1 and alpha 2 subunit mRNA may become a reliable indicator of insomnia disorder.

Automated summary

The study aimed to investigate the changes in various indexes of the GABAergic system in the peripheral blood of patients with insomnia disorder and identify related factors. The results showed that the mRNA levels of GABA(A) receptor alpha 1 and alpha 2 subunits were significantly lower in the insomnia disorder group compared to the normal control group. However, there was no significant difference in serum GABA levels between the two groups. Moreover, there was no significant correlation between the GABA levels and the mRNA expression levels of alpha 1 and alpha 2 subunits of GABA(A) receptors in the insomnia disorder group.