Estradiol Valerate and Remifemin ameliorate ovariectomy-induced decrease in a serotonin dorsal raphe-preoptic...

Area of Science:

• Neuroendocrinology
• Reproductive Biology
• Pharmacology

Background:

• Perimenopausal syndromes, including hot flashes, arise from declining ovarian function.
• Serotonin pathway alterations in the hypothalamus are implicated in the mechanism of hot flashes.

Purpose of the Study:

• To investigate the role of the serotonin dorsal raphe-preoptic hypothalamus pathway in an animal model of menopause-induced hot flashes.
• To explore the therapeutic effects of estradiol valerate and Remifemin on this pathway.

Main Methods:

• Ovariectomized (OVX) rats were used as a menopausal model.
• Serotonin expression in the dorsal raphe (DR) and preoptic anterior hypothalamus (POAH) was assessed using immunofluorescence and ELISA.
• Therapeutic effects of estradiol and Remifemin were evaluated, along with neuronal tracing studies.

Main Results:

• Ovariectomy significantly decreased serotonin levels in the DR and serotonin-positive fibers in the POAH.
• Both estradiol and Remifemin treatments reversed these OVX-induced decreases, restoring serotonin levels to those of sham-operated rats.
• Both treatments also countered the reduction in serotonin-expressing neurons projecting to the ventrolateral preoptic nucleus (VLPO).

Conclusions:

• Ovariectomy alters the central serotonin pathway, affecting serotonin synthesis and fiber distribution in key brain regions.
• Estradiol and Remifemin demonstrate equivalent therapeutic efficacy in normalizing these serotonin pathway changes.
• This suggests the serotonin pathway is a viable target for managing menopausal hot flashes.