Assessment of neurotransmitter imbalances within the anterior cingulate cortex in women with primary dysmenorrhea: An initial proton magnetic resonance spectroscopy study

Purpose: The neural pathophysiology underlying primary dysmenorrhea (PDM), which leads to poor mode and changes in central pain modulatory systems, remains largely unknown. The objective of this study was to investigate the changes in glutamate/glutamine (Glx) and gamma-aminobutyric acid (GABA+) levels within anterior cingulate cortex (ACC), and their associations with clinical indicators in PDM women.Methods: Using 3 T proton magnetic resonance spectroscopy (1H-MRS), we acquired and compared ACC-Glx and ACC-GABA+ levels in PDMs (N = 41) and age- and education-matched healthy controls (HCs) (N = 39) during both the menstrual and periovulatory phases, and between menstrual and periovulatory phases within each group. Total creatine (Cr referencing) level was used as an endogenous reference. The correlations of ACC-neurotransmitter levels with clinical characteristics and the correlations of ACC-Glx with ACC-GABA+ levels in the two groups were analyzed.Results: Compared to HCs or the periovulatory phase, PDMs exhibited significantly increased ACC-Glx levels (p < 0.05) during the menstrual phase. Positive correlations between GABA+ and Glx levels (r = 0.385, p = 0.025) were found in PDMs during the menstrual phase. ACC-GABA+ levels were associated with self-rating distress scale (SDS) scores (GABA+/Cr: r = 0.369, p = 0.045) and pain catastrophizing scale (PCS) scores (GABA+/Cr: r = 0.373, p = 0.042) in PDM group in only the menstrual phase.Conclusion: Our study represents the first report of ACC-GABA+/Glx imbalances in PDMs during the menstrual phase, which may underlie the mechanisms mediating depression and painful catastrophic symptoms.

Automated summary

This study investigated the changes in glutamate/glutamine (Glx) and gamma-aminobutyric acid (GABA+) levels within the anterior cingulate cortex (ACC) in primary dysmenorrhea (PDM) women. The findings showed that PDM women had significantly increased ACC-Glx levels during the menstrual phase and a positive correlation between GABA+ and Glx levels in PDM women during this phase. Additionally, ACC-GABA+ levels were associated with self-rating distress scale scores and pain catastrophizing scale scores in PDM women during the menstrual phase.