In Adult Rats With Polycystic Ovarian Syndrome, Unilateral or Bilateral Vagotomy Modifies the Noradrenergic Concentration in the Ovaries and the Celiac Superior Mesenteric Ganglia in Different Ways.

Rosa Linares,Carolina Morán,Gabriela Rosas,Elizabeth Vieyra,Daniel R Velázquez,Leticia Morales-Ledesma,Roberto Domínguez,Julieta A Espinoza,Deyra A Ramírez

doi:10.3389/fphys.2019.01309

Abstract

In rats with polycystic ovarian syndrome (PCOS) induced by estradiol valerate (EV) injection, sectioning of the vagus nerve in the juvenile stage restores ovulatory function, suggesting that the vagus nerve stimulates the onset and development of PCOS. We analyzed whether in adult rats, the role played by the vagus nerve in PCOS development is associated with the nerve’s regulation of noradrenergic activity in the celiac superior mesenteric ganglion (CSMG). Ten-day-old rats were injected with corn oil [vehicle (Vh)] or EV (2 mg). At 76 days of age, rats injected with Vh or EV were subjected to sham surgery or the sectioning of one or both vagus nerves (vagotomy). The animals were sacrificed at 80–82 days of age at vaginal estrus smear. Compared to Vh-treated animals, EV-induced PCOS rats showed a lack of ovulation, the presence of follicular cysts, and a high concentration of testosterone, without changes in noradrenaline concentrations in the CSMG or ovaries. In PCOS rats, sham surgery lowered serum testosterone and noradrenaline concentrations in the CSMG but did not restore ovulation. In animals with PCOS, vagotomy lowered testosterone concentrations to a larger degree than in sham-surgery animals. The ovaries of rats with PCOS and vagotomy showed fresh corpora lutea, indicating ovulation. In EV-treated rats with unilateral vagotomy, the concentration of noradrenaline in the CSMG was similar to that in rats with PCOS and sham surgery, which did not ovulate, while in the ovaries of PCOS rats with left or bilateral vagotomy, the noradrenaline concentration was lower than that in sham-surgery-treated animals. Our results suggest that the vagus nerve regulates PCOS development through a different mechanism than the increase in the noradrenergic activity in the CSMG; however, in ovaries, the restoration of ovulation is associated with a decrease in ovarian noradrenaline.

Highlights

Evidence on the functional interaction between the peripheral nervous system and the reproductive system has been published (Domínguez and Riboni, 1971; Gerendai et al, 2000, 2009; Sosa et al, 2000; Casais et al, 2006)
We have previously shown that in 24-day-old rats with estradiol valerate (EV)-induced polycystic ovarian syndrome (PCOS), the unilateral or bilateral sectioning of the vagus nerve resulted in spontaneous ovulation in both ovaries (Linares et al, 2013) and decreased the noradrenaline concentration in the celiac superior mesenteric ganglion (CSMG) when the animal reached adulthood (Linares et al, 2017)
The supernatant was filtered using 0.2 μm regenerated cellulose filters. Twenty microliters of this extract was injected into a chromatography column via Effects of Sham Surgery in Vh- or EV-Treated Rats. Regardless of whether they were subjected to sham surgery, the rats injected with EV did not present oocytes in the oviducts or corpora lutea in the ovaries (Table 1)

Summary

Introduction

Evidence on the functional interaction between the peripheral nervous system and the reproductive system has been published (Domínguez and Riboni, 1971; Gerendai et al, 2000, 2009; Sosa et al, 2000; Casais et al, 2006). Experimental and clinical studies have shown the presence of multiple interactions between the sympathetic and parasympathetic nervous system, which are regulated through various pathways and mechanisms at the central and peripheral levels of the neuroaxis (Langer and Hicks, 1984; Myslivecek and Trojan, 2003). According to Ondicova and Mravec (2010), the peripheral interactions between the peripheral sympathetic and parasympathetic systems are based on the morphologicalfunctional organization of the pathways. These interactions may be realized at the levels of the sympathetic prevertebral ganglia and neuroeffector connections. The CSMG has a profuse capillary plexus forming circulatory microcircuits among the different ganglionic structures (Tanaka and Chiba, 1996)

Methods

Results

Discussion

Conclusion