A possible dual regulation of prolactin release by the serotoninergic system in rats at pro-oestrus and during late pregnancy: role of ovarian hormones

Jahn, Graciela A.; Deis, R. P.

doi:10.1677/joe.0.1120367

Cited by 16 publications

(9 citation statements)

References 25 publications

(43 reference statements)

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“…This finding is consistent with other studies showing that not only estradiol but also progesterone can alter serotonergic neurotransmission. A stimulatory role for progesterone in the regulation of 5-HT synthesis has been demonstrated (Jahn and Deis, 1987), even though progesterone appears to have no effect on the translation of the serotonin-synthesizing enzyme, tryptophan hydroxylase (Bethea et al, 2000). Our data show that progesterone, similar to estrogen, interferes with the ability of an SSRI to block SERT function.…”

Section: Discussionmentioning

confidence: 48%

Impact of Ovarian Hormones on the Modulation of the Serotonin Transporter by Fluvoxamine

Benmansour

Piotrowski

Altamirano

et al. 2008

Neuropsychopharmacol

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Most preclinical studies examining the mechanism(s) of action of antidepressants are carried out using male animals. Blockade of serotonin transporter (SERT) function by selective serotonin reuptake inhibitors (SSRIs) is the initial event that triggers a not completely understood process that results in clinical improvement in depression. To investigate whether there are differences in the ability of SSRIs to inhibit the SERT between male and female rats at different phases of the estrous cycle, clearance of locally applied serotonin (5-HT) was measured by in vivo chronoamperometry. Local application of the SSRI, fluvoxamine, directly into the CA3 area of hippocampus increased significantly 5-HT clearance time parameters in male rats and female rats in estrus or diestrus, but not in proestrus. The contribution of ovarian steroids to this result was investigated in ovariectomized (OVX) rats treated with estradiol benzoate (EB) and/or progesterone (P). In OVX-control rats, fluvoxamine increased clearance time parameters, whereas EB and/or P treatment blocked this effect, consistent with what was seen in female rats in proestrus. This effect was gender-specific, since treatment of castrated rats with EB/ P had no effect on the ability of fluvoxamine to slow 5-HT clearance. The time course of hormonal effects showed that 1-60 min after local application of 17-b-estradiol (E 2 ) into the CA3 region of OVX rats, fluvoxamine had no effect on clearance time of 5-HT. E 2 -BSA mimicked E 2 's effects at 10 min but not at 60 min. Pretreatment with estrogen receptor antagonists blocked the effects of E 2 . The finding that acutely both estradiol and progesterone can inhibit the ability of an SSRI to slow the clearance of 5-HT, may have important implications for the use of SSRIs in women.

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Section: Discussionmentioning

confidence: 48%

Impact of Ovarian Hormones on the Modulation of the Serotonin Transporter by Fluvoxamine

Benmansour

Piotrowski

Altamirano

et al. 2008

Neuropsychopharmacol

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“…In addition, P partially blocks the effect of pCPA, a serotonin synthesis inhibitor, on hypothalamic serotonin levels, and an antiprogestin reduced hypothalamic levels of 5HIAA, a serotonin metabolite (Walker and Wilson, 1983). Moreover, the proestrus surge of prolactin is inhibited by pCPA treatment, and this effect is completely reversed by P treatment (Jahn and Deis, 1987). Together, these data support a stimulatory role for P in the regulation of serotonin synthesis.…”

Section: Relation To Other Studiesmentioning

confidence: 58%

Ovarian Steroid Regulation of Tryptophan Hydroxylase mRNA Expression in Rhesus Macaques

et al. 1996

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Progesterone (P) stimulates prolactin secretion through an unknown neural mechanism in estrogen (E)-primed female monkeys. Serotonin is a stimulatory neurotransmitter in prolactin regulation, and this laboratory has shown previously that E induces progestin receptors (PR) in serotonin neurons. Therefore, we questioned whether E and/or EϩP increased serotonin neural function. The expression of mRNA for tryptophan hydroxylase (TPH) was examined in ovariectomized (spayed) control, E-treated (28 d), and EϩP-treated monkeys (14 d E and 14 d EϩP) using in situ hybridization and a 249 bp TPH cRNA probe generated with RT-PCR (n ϭ 5 animals/group). Densitometric analysis of film autoradiographs revealed a ninefold increase in TPH mRNA in E-treated macaques compared to spayed animals ( p Ͻ 0.05). With supplemental P treatment, TPH mRNA signal was increased fivefold over spayed animals ( p Ͻ 0.05), but was not significantly different compared to E-treated animals. These results were verified by grain counts from photographic emulsion-coated slides. There were significantly higher single-cell levels of TPH mRNA in serotonergic neurons of the dorsal raphe in E-and EϩP-treated groups ( p Ͻ 0.05). These data indicate that E induces TPH gene expression in nonhuman primates and that the addition of P has little additive effect on TPH gene expression. Thus, the action of P on prolactin secretion is probably not mediated at the level of TPH gene transcription. However, because P increases raphe serotonin content in E-primed rodents, the possibility remains that P may have other actions on post-translational processing or enzyme activity.

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“…Blood samples were taken 35 h after pCPA injection (at 18.00 h on days 3, 6, or 17, respectively). Results from our laboratory have shown previously [14] that, under these conditions, pC'PA modifies the PRL concentra tions in pregnant rats. It has been shown also that lower doses of pC'PA (i.c.. 150 mg/kg) can decrease significantly the concentration of the metabolite of serotonin, 5-hydroxyindoleacetic acid, in cere brospinal fluid of conscious rats 24 h later [21 ].…”

Section: Drug Treatmentsmentioning

confidence: 66%

“…The most important neurotransmit ters stimulating PRL secretion are the opioid peptides [11. 12] and serotonin [13][14][15], It has been shown that in the arcuate nucleus the neurons responsible for producing opioid peptides are able to concentrate estrogens [ 16], On the other hand, serotonin neurons participate in the proestrous surge of PRL and in the PRL secretion in duced by administration of estrogen to ovariectomized rats, while progesterone enhances these actions [17], However, it has been shown that both serotoninergic [14,15] and opioid [18,19] systems may inhibit PRL secre tion under certain conditions. The aim of this study was to determine the pattern of PRL secretion induced by the central action of estradiol and the participation of opioid and sertoninergic systems in regulating this secretion.…”

Section: Introductionmentioning

confidence: 99%

Participation of Opioid and Serotoninergic Systems in Prolactin Secretion Induced by Hypothalamic Action of Estradiol

Carón

Deis²

1996

Neuroendocrinology

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The aim of the present study was to determine the central effect of estradiol (E₂) on the pattern of secretion of prolactin (PRL) in virgin rats and the participation of opioid and serotoninergic systems in the regulation of this secretion. Bilateral cannulae containing E₂ (group E) or cholesterol (group C) were implanted in the arcuate nucleus on the day of estrus (day 0). Blood samples were obtained at 09.00, 14.00, or 18.00 h on days 1, 3, 6, or 9. All rats were blood sampled once. In group E, the PRL levels at 09.00 h on days 1 and 3 were similar to those from group C. However, higher values were obtained at 14.00 and 18.00 h, thus showing a diurnal rhythm with low levels in the morning and high values during the afternoon. No rhythm in PRL secretion was observed on days 6 and 9 in group E in which serum PRL was similarly increased with respect to group C at all times. The progesterone (P) levels paralleled PRL concentration, being significantly higher in group E at 18.00 h on day 1 at 14.00 and 18.00 h on day 3, and at all three times on days 6 and 9; the P measurements were consistent with luteotropic actions of PRL. Naloxone (NAL; 2 mg/kg i.p.) was injected at 17.30 h on days 3, 6, or 17, and 30 min later the animals were blood sampled. P-Chlorophenylalanine (pCPA; 200 mg/ kg s.c.) was administered at 07.00 h on days 2, 5, or 16, and blood samples were taken 35 h later. Control E rats were injected with vehicle and blood sampled at 18.00 h on days 3, 6, or 17. The PRL increase induced by E₂ at 18.00 h on days 3 and 6 was not modified by pretreatment with NAL or pCPA. Serum P was significantly reduced after pCPA administration on days 3 and 6 and after NAL only on day 6. The increase in PRL at 18.00h on day 17 induced by E₂ was dramatically enhanced by NAL or pCPA, while these treatments did not significantly modify serum P levels. Our results indicate an inhibitory influence from both opioid and serotoninergic systems on PRL secretion induced by the long-term application of E₂ in the arcuate nucleus.

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A possible dual regulation of prolactin release by the serotoninergic system in rats at pro-oestrus and during late pregnancy: role of ovarian hormones

Cited by 16 publications

References 25 publications

Impact of Ovarian Hormones on the Modulation of the Serotonin Transporter by Fluvoxamine

Impact of Ovarian Hormones on the Modulation of the Serotonin Transporter by Fluvoxamine

Ovarian Steroid Regulation of Tryptophan Hydroxylase mRNA Expression in Rhesus Macaques

Participation of Opioid and Serotoninergic Systems in Prolactin Secretion Induced by Hypothalamic Action of Estradiol

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