How does allopregnanolone help with PMDD symptoms?

Background: Premenstrual dysphoric disorder (PMDD) is a common mental health challenge among women of reproductive age. Allopregnanolone (3α, 5α-THP; ALLO) mediated functional alterations of GABAA receptors (GABAA-R) are involved in PMDD pathogenesis, however, the specific mechanism remains unknown. Therefore, we investigated the role of ALLO mediated GABAA-Rα4 in the pathophysiology of PMDD. Purpose: We determined whether the pathogenesis of PMDD is associated with ALLO mediated GABAA-Rα4 expression changes in different brain regions. Methods: Rat models of PMDD liver-qi invasion syndrome (PMDD-LIS) were established via the resident intruder paradigm. Behavioral changes of rats were assessed by aggressive behavior tests, EPM and OFT. The levels of progesterone and ALLO in serum as well as brain areas were determined by ELISA. Variations in GABAA-Rα4 levels in brain regions were assessed by immunofluorescence and RT-PCR. Medicated serum was used to interfere with rat hippocampal neurons, and changes in Cl - current were recorded through electrophysiology. Results: Premenstrual anxiety and irritability of PMDD-LIS patients can be simulated in PMDD-LIS rat models. Exogenous ALLO significantly improved the anxiety behaviors of PMDD-LIS rats. Changes in ALLO among different brain regions varied. GABAA-Rα4 expressions were low in the amygdala and abnormally high in the hippocampus, however, ALLO alleviated these deviations. Whole-cell patch clamp recording technique showed a weaker Cl - current intensity of PMDD-LIS rats, reduced neuroinhibitory functions and increased Cl - current intensity in the ALLO group drug serum intervention and enhanced emotional inhibition function. Conclusion: We established that ALLO regulation of the GABAA-Rα4 subunit in the amygdala and hippocampus is involved in PMDD-LIS pathogenesis.

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