Role of Serotonin in the Regulation of Ovulation

Markó, M.; Flückiger, E.

doi:10.1159/000123005

Cited by 31 publications

(11 citation statements)

References 8 publications

(10 reference statements)

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“…possibly because of a blockade of its re lease [25]. However, they conflict with the results showing that 5-HT exerts a facilitatory role on the mechanisms controlling ovulation and gonadotropin secretion [9,10,17,19,30,31,51]. The mechanisms underlying these two opposite effects of se rotonin on LH secretion have not been completely established although antagonist responses have been evoked from the dor sal and medial raphe nuclei [33].…”

Section: Discussionmentioning

confidence: 84%

Inhibition of Proestrous LH Surge and Ovulation in Rats Evoked by Stimulation of the Medial Raphe Nucleus Involves a GABA-Mediated Mechanism

et al. 1989

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The neurotransmitters involved in the inhibition of luteinizing hormone (LH) release induced by electrochemical stimulation (anodic d.c, 100 µA/30 s) of the medial raphe nucleus (MRn) were studied. Stimulation applied at noon on the day of proestrus blocked the preovulatory surge of LH and ovulation. This effect was prevented by pretreating the animals (15 min before stimulation) with the 5-HT antagonist, methysergide (3.5 mg/kg, i.p.) The inhibition of LH release induced by stimulation of the MRn was also suppressed by the injection of the γ-aminobutyric acid (GABA) antagonists, picrotoxin (0.8 mg/kg, i.p.) and bicuculline (6 mg/kg, i.p.). Injection of 5-HT(15 µg) into the third ventricle on the day of proestrus mimicked the effect of MRn stimulation, a response which was prevented by methysergide, picrotoxin or bicuculline. An intraventricular injection of GABA (10 µg) also inhibited the preovulatory surge of LH and ovulation, but whereas the administration of bicuculline prevented the effect of GABA, that of methysergide failed to produce any change. It is concluded that stimulation of the MRn inhibits the proestrous surge of LH by activating a serotonergic pathway and that the effect is mediated by GABAergic neurons.

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Section: Discussionmentioning

confidence: 84%

Inhibition of Proestrous LH Surge and Ovulation in Rats Evoked by Stimulation of the Medial Raphe Nucleus Involves a GABA-Mediated Mechanism

et al. 1989

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“…The effect of these drugs is reversed by 5-HTP administered intraperitoneally or intraventricularly (Hery, Laplante & Kordon, 1976;Coen & MacKinnon, 1979;Chen, Sylvester, Ieiri & Meites, 1981). Moreover, several serotonin antagonists have been reported to block ovulation in rats (Hery et al 1976;Marko & Fluckiger, 1980). In this connection Marko & Fluckiger (1980) underline the positive correlation between the serotonin antagonistic activity of these drugs and their capability for blocking ovulation.…”

Section: Introductionmentioning

confidence: 91%

Role of serotoninergic neurones in the control of gonadotrophin and prolactin secretion in the rat

Rúzsás¹,

Limonta²,

Martini³

1982

Journal of Endocrinology

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The role of brain serotonin (5-hydroxytryptamine, 5-HT) in the control of LH, FSH and prolactin secretion was studied in two groups of experimental animals: intact adult male rats and ovariectomized adult female rats. 5-Hydroxytryptophan (5-HTP), a precursor of serotonin synthesis, and fluoxetine, a specific inhibitor of 5-HT uptake, were given either alone or together. 5\ x =r eq-\ Hydroxytryptophan (50 mg/kg) was administered intraperitoneally and fluoxetine (20 \g=m\g/rat) was given into one of the lateral ventricles of the brain. Neither 5-HTP nor fluoxetine given alone affected LH secretion but combined treatment with the two drugs elicited a significant increase in serum LH levels in both intact male and ovariectomized female rats. Fluoxetine and 5-HTP, alone or together, did not modify FSH secretion in either kind of animal. In intact males and in ovariectomized females, 5-HTP induced a significant increase in prolactin release; fluoxetine alone was ineffective. In male animals treated with fluoxetine plus 5-HTP, serum prolactin levels increased but such an increase was lower than that found in the animals treated only with 5-HTP. In ovariectomized rats, the combined treatment induced an increase in serum prolactin levels similar to that found in animals treated with 5-HTP alone.These data suggested that brain serotonin exerts a stimulating effect on LH secretion in both intact male and ovariectomized rats, but that it does not play any role in the control of FSH release in either kind of animal and that central serotoninergic pathways participate in the stimulating control of prolactin release from the anterior pituitary gland. However, some of the data also suggested the possibility of the existence in the brain of serotoninergic systems inhibiting prolactin secretion.

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“…These results suggest that 5-HT in the median eminence is involved in the control of gonadotropin release. The data further suggest that 5-HT does not act directly on the anterior pituitary to modulate gonadotropin or prolactin release.The participation of serotonin (5-HT) in the control of phasic release of luteinizing hormone (LH) appears widely accepted [3,21,23,40]. However, no unanimity of opinion exists wheter 5-HT is stimulatory [9,11,24,39] or inhibitory [ 1.6 ,1 0 ,12] on LH release.…”

mentioning

confidence: 99%

Median Eminence Serotonin Involved in the Proestrus Gonadotropin Release

Ml¹,

M²,

Chiocchio³

et al. 1984

Neuroendocrinology

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Numerous studies have suggested that serotonin (5-HT) is involved in the regulation of anterior pituitary hormone release. In the present study, the 5-HT concentrations of the median eminence and anterior pituitary lobe were measured during the estrous cycle and lactation in order to correlate changes in 5-HT levels with changes in serum luteinizing hormone, follicle-stimulating hormone, and prolactin. On the day of proestrus, median eminence 5-HT concentrations declined significantly between 14.00 and 16.30 h at the beginning of the gonadotropin and prolactin surges. No changes in 5-HT concentrations were found between the morning and afternoon on other days of the cycle. In the anterior pituitary, the levels of 5-HT did not change during the estrous cycle. 5-HT turnover rates were also estimated in the median eminence on proestrus and diestrus 1. The median eminence 5-HT synthesis rate increased in the afternoon of proestrus at 16.30 h. 5-HT was also measured in the anterior pituitary and the median eminence of lactating rats in four experimental situations: mothers with their litter until decapitation, mothers separated from their pups 4 h earlier, and mothers separated from their pups 4 h earlier, after which the pups were allowed to suckle for 5 or 30 min. In spite of the acute changes in circulating prolactin, 5-HT levels in the median eminence were not affected in any situation studied. These results suggest that 5-HT in the median eminence is involved in the control of gonadotropin release. The data further suggest that 5-HT does not act directly on the anterior pituitary to modulate gonadotropin or prolactin release.

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Role of Serotonin in the Regulation of Ovulation

Cited by 31 publications

References 8 publications

Inhibition of Proestrous LH Surge and Ovulation in Rats Evoked by Stimulation of the Medial Raphe Nucleus Involves a GABA-Mediated Mechanism

Inhibition of Proestrous LH Surge and Ovulation in Rats Evoked by Stimulation of the Medial Raphe Nucleus Involves a GABA-Mediated Mechanism

Role of serotoninergic neurones in the control of gonadotrophin and prolactin secretion in the rat

Median Eminence Serotonin Involved in the Proestrus Gonadotropin Release

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