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Avona A, Mason BN, Burgos-Vega C, Hovhannisyan AH, Belugin SN, Mecklenburg J, Goffin V, Wajahat N, Price TJ, Akopian AN, Dussor G. Meningeal CGRP-Prolactin Interaction Evokes Female-Specific Migraine Behavior. Ann Neurol 2021; 89:1129-1144. [PMID: 33749851 PMCID: PMC8195469 DOI: 10.1002/ana.26070] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Migraine is three times more common in women. CGRP plays a critical role in migraine pathology and causes female-specific behavioral responses upon meningeal application. These effects are likely mediated through interactions of CGRP with signaling systems specific to females. Prolactin (PRL) levels have been correlated with migraine attacks. Here, we explore a potential interaction between CGRP and PRL in the meninges. METHODS Prolactin, CGRP, and receptor antagonists CGRP8-37 or Δ1-9-G129R-hPRL were administered onto the dura of rodents followed by behavioral testing. Immunohistochemistry was used to examine PRL, CGRP and Prolactin receptor (Prlr) expression within the dura. Electrophysiology on cultured and back-labeled trigeminal ganglia (TG) neurons was used to assess PRL-induced excitability. Finally, the effects of PRL on evoked CGRP release from ex vivo dura were measured. RESULTS We found that dural PRL produced sustained and long-lasting migraine-like behavior in cycling and ovariectomized female, but not male rodents. Prlr was expressed on dural afferent nerves in females with little-to-no presence in males. Consistent with this, PRL increased excitability only in female TG neurons innervating the dura and selectively sensitized CGRP release from female ex vivo dura. We demonstrate crosstalk between PRL and CGRP systems as CGRP8-37 decreases migraine-like responses to dural PRL. Reciprocally, Δ1-9-G129R-hPRL attenuates dural CGRP-induced migraine behaviors. Similarly, Prlr deletion from sensory neurons significantly reduced migraine-like responses to dural CGRP. INTERPRETATION This CGRP-PRL interaction in the meninges is a mechanism by which these peptides could produce female-selective responses and increase the prevalence of migraine in women. ANN NEUROL 2021;89:1129-1144.
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Affiliation(s)
- Amanda Avona
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX
| | - Bianca N. Mason
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX
| | - Carolina Burgos-Vega
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX
| | - Anahit H. Hovhannisyan
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Sergei N. Belugin
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Jennifer Mecklenburg
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | | | - Naureen Wajahat
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX
| | - Theodore J. Price
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX
| | - Armen N. Akopian
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Gregory Dussor
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX
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Silva JF, Henriques PC, Campideli-Santana AC, Araujo-Lopes R, Aquino NSS, Hipolito LTM, Lopes-Aguiar C, Reis AM, Grattan DR, Szawka RE. Estradiol Potentiates But Is Not Essential for Prolactin-Induced Suppression of Luteinizing Hormone Pulses in Female Rats. Endocrinology 2020; 161:5735034. [PMID: 32052048 DOI: 10.1210/endocr/bqaa022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 02/10/2020] [Indexed: 12/17/2022]
Abstract
Hyperprolactinemia causes infertility by suppressing gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion. Because effects of prolactin (PRL) on the hypothalamus usually require estradiol (E2), we investigated the role of E2 in PRL-induced suppression of LH pulses. Ovariectomized (OVX) rats treated with oil or E2 (OVX + E2) received a subcutaneous injection of ovine PRL (oPRL) 30 minutes before serial measurement of LH in the tail blood by enzyme-linked immunosorbent assay. E2 reduced pulsatile LH secretion. oPRL at 1.5 mg/kg further reduced LH pulse frequency in OVX + E2 but had no effect in OVX rats. The higher dose of 6-mg/kg oPRL decreased LH pulse frequency in both OVX and OVX + E2 rats, whereas pulse amplitude and mean LH levels were lowered only in OVX + E2 rats. Kisspeptin immunoreactivity and Kiss1 messenger ribonucleic acid (mRNA) levels were decreased in the arcuate nucleus (ARC) of OVX + E2 rats. oPRL decreased both kisspeptin peptide and gene expression in the ARC of OVX rats but did not alter the already low levels in OVX + E2 rats. In the anteroventral periventricular nucleus, oPRL did not change kisspeptin immunoreactivity and, paradoxically, increased Kiss1 mRNA only in OVX + E2 rats. Moreover, oPRL effectively reduced Gnrh expression regardless of E2 treatment. In this study we used tail-tip blood sampling to determine the acute effect of PRL on LH pulsatility in female rats. Our findings characterize the role of E2 in the PRL modulation of hypothalamic components of the gonadal axis and LH release, demonstrating that E2 potentiates but is not essential for the suppression of pulsatile LH secretion caused by hyperprolactinemia.
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Affiliation(s)
- Juneo F Silva
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Centro de Microscopia Eletronica, Departamento de Ciencias Biologicas, Universidade Estadual de Santa Cruz, Campus Soane Nazare de Andrade, Ilheus, Brazil
| | - Patricia C Henriques
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ana C Campideli-Santana
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Roberta Araujo-Lopes
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Nayara S S Aquino
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Laisa T M Hipolito
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Cleiton Lopes-Aguiar
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Adelina M Reis
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Raphael E Szawka
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Adaptive Resetting of Tuberoinfundibular Dopamine (TIDA) Network Activity during Lactation in Mice. J Neurosci 2020; 40:3203-3216. [PMID: 32209609 DOI: 10.1523/jneurosci.1553-18.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 01/22/2023] Open
Abstract
Giving birth triggers a wide repertoire of physiological and behavioral changes in the mother to enable her to feed and care for her offspring. These changes require coordination and are often orchestrated from the CNS, through as of yet poorly understood mechanisms. A neuronal population with a central role in puerperal changes is the tuberoinfundibular dopamine (TIDA) neurons that control release of the pituitary hormone, prolactin, which triggers key maternal adaptations, including lactation and maternal care. Here, we used Ca2+ imaging on mice from both sexes and whole-cell recordings on female mouse TIDA neurons in vitro to examine whether they adapt their cellular and network activity according to reproductive state. In the high-prolactin state of lactation, TIDA neurons shift to faster membrane potential oscillations, a reconfiguration that reverses upon weaning. During the estrous cycle, however, which includes a brief, but pronounced, prolactin peak, oscillation frequency remains stable. An increase in the hyperpolarization-activated mixed cation current, Ih, possibly through unmasking as dopamine release drops during nursing, may partially explain the reconfiguration of TIDA rhythms. These findings identify a reversible plasticity in hypothalamic network activity that can serve to adapt the dam for motherhood.SIGNIFICANCE STATEMENT Motherhood requires profound behavioral and physiological adaptations to enable caring for offspring, but the underlying CNS changes are poorly understood. Here, we show that, during lactation, neuroendocrine dopamine neurons, the "TIDA" cells that control prolactin secretion, reorganize their trademark oscillations to discharge in faster frequencies. Unlike previous studies, which typically have focused on structural and transcriptional changes during pregnancy and lactation, we demonstrate a functional switch in activity and one that, distinct from previously described puerperal modifications, reverses fully on weaning. We further provide evidence that a specific conductance (Ih) contributes to the altered network rhythm. These findings identify a new facet of maternal brain plasticity at the level of membrane properties and consequent ensemble activity.
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Phillipps HR, Yip SH, Grattan DR. Patterns of prolactin secretion. Mol Cell Endocrinol 2020; 502:110679. [PMID: 31843563 DOI: 10.1016/j.mce.2019.110679] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 12/11/2022]
Abstract
Prolactin is pleotropic in nature affecting multiple tissues throughout the body. As a consequence of the broad range of functions, regulation of anterior pituitary prolactin secretion is complex and atypical as compared to other pituitary hormones. Many studies have provided insight into the complex hypothalamic-pituitary networks controlling prolactin secretion patterns in different species using a range of techniques. Here, we review prolactin secretion in both males and females; and consider the different patterns of prolactin secretion across the reproductive cycle in representative female mammals with short versus long luteal phases and in seasonal breeders. Additionally, we highlight changes in the pattern of secretion during pregnancy and lactation, and discuss the wide range of adaptive functions that prolactin may have in these important physiological states.
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Affiliation(s)
- Hollian R Phillipps
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - Siew H Yip
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand.
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Camilletti MA, Abeledo-Machado A, Ferraris J, Pérez PA, Faraoni EY, Pisera D, Gutierrez S, Díaz-Torga G. Role of GPER in the anterior pituitary gland focusing on lactotroph function. J Endocrinol 2019; 240:99-110. [PMID: 30400046 DOI: 10.1530/joe-18-0402] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 10/19/2018] [Indexed: 12/22/2022]
Abstract
Ovarian steroids control a variety of physiological functions. They exert actions through classical nuclear steroid receptors, but rapid non-genomic actions through specific membrane steroid receptors have been also described. In this study, we demonstrate that the G-protein-coupled estrogen receptor (GPER) is expressed in the rat pituitary gland and, at a high level, in the lactotroph population. Our results revealed that ~40% of the anterior pituitary cells are GPER positive and ~35% of the lactotrophs are GPER positive. By immunocytochemical and immuno-electron-microscopy studies, we demonstrated that GPER is localized in the plasmatic membrane but is also associated to the endoplasmic reticulum in rat lactotrophs. Moreover, we found that local Gper expression is regulated negatively by 17β-estradiol (E2) and progesterone (P4) and fluctuates during the estrus cycle, being minimal in proestrus. Interestingly, lack of ovarian steroids after an ovariectomy (OVX) significantly increased pituitary GPER expression specifically in the three morphologically different subtypes of lactotrophs. We found a rapid estradiol stimulatory effect on PRL secretion mediated by GPER, both in vitro and ex vivo, using a GPER agonist G1, and this effect was prevented by the GPER antagonist G36, demonstrating a novel role for this receptor. Then, the increased pituitary GPER expression after OVX could lead to alterations in the pituitary function as all three lactotroph subtypes are target of GPER ligand and could be involved in the PRL secretion mediated by GPER. Therefore, it should be taken into consideration in the response of the gland to an eventual hormone replacement therapy.
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Affiliation(s)
- María Andrea Camilletti
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Alejandra Abeledo-Machado
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Jimena Ferraris
- Instituto de Investigaciones Biomédicas, Facultad de Medicina, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Pablo A Pérez
- Centro de Microscopia Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Medicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Erika Y Faraoni
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Daniel Pisera
- Instituto de Investigaciones Biomédicas, Facultad de Medicina, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Silvina Gutierrez
- Centro de Microscopia Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Medicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Graciela Díaz-Torga
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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Calvino C, Império GE, Wilieman M, Costa-E-Sousa RH, Souza LL, Trevenzoli IH, Pazos-Moura CC. Hypothyroidism Induces Hypophagia Associated with Alterations in Protein Expression of Neuropeptide Y and Proopiomelanocortin in the Arcuate Nucleus, Independently of Hypothalamic Nuclei-Specific Changes in Leptin Signaling. Thyroid 2016; 26:134-43. [PMID: 26538454 DOI: 10.1089/thy.2015.0384] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Thyroid hormone and leptin are essential regulators of energy homeostasis. Both hormones stimulate energy expenditure but have opposite effects on appetite. The mechanisms behind food intake regulation in thyroid dysfunctions are poorly understood. It has been shown that hypothyroid rats exhibited impaired leptin anorexigenic effect and signaling in total hypothalamus, even though they were hypophagic. It was hypothesized that hypothyroidism modulates the expression of neuropeptides: orexigenic neuropeptide Y (NPY) and anorexigenic proopiomelanocortin (POMC), independently of inducing nuclei-specific changes in hypothalamic leptin signaling. METHODS Adult male rats were rendered hypothyroid by administration of 0.03% methimazole in the drinking water for 21 days. Protein content of NPY, POMC, and leptin signaling (the signal transducer and activator of transcription 3 [STAT3] pathway) were evaluated by Western blot, and mRNA levels by real time reverse transcription polymerase chain reaction in arcuate (ARC), ventromedial (VMN), and paraventricular (PVN) hypothalamic nuclei isolated from euthyroid (eu) and hypothyroid (hypo) rats. Leptin anorexigenic effect was tested by recording food intake for two hours after intracerebroventricular (i.c.v.) administration of leptin. Statistical differences were considered significant at p ≤ 0.05. RESULTS Hypothyroidism was confirmed by decreased serum triiodothyronine, thyroxine, and increased thyrotropin, in addition to increased levels of pro-TRH mRNA in PVN and Dio2 mRNA in the ARC of hypo rats. Hypothyroidism decreased body weight and food intake associated with decreased protein content of NPY and increased content of POMC in the ARC. Conversely, hypothyroidism induced central resistance to the acute anorexigenic effect of leptin, since while euthyroid rats displayed reduced food intake after leptin i.c.v. injection, hypothyroid rats showed no response. Hypothyroid rats exhibited decreased leptin receptor (ObRb) protein content in ARC and VMN but not in PVN nucleus. ObRb protein changes were concomitant with decreased phosphorylated STAT3 in the ARC, and decreased total STAT3 in VMN and PVN. However, hypothyroidism did not affect mRNA levels of Lepr or Stat3 in the hypothalamic nuclei. CONCLUSIONS Experimental hypothyroidism induced a negative energy balance accompanied by decreased NPY and increased POMC protein content in the ARC, resulting in predominance of anorexigenic pathways, despite central leptin resistance and impairment of the leptin signaling cascade in a nuclei-specific manner.
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Affiliation(s)
- Camila Calvino
- 1 Laboratory of Molecular Endocrinology, Federal University of Rio de Janeiro , Rio de Janeiro, Brazil
| | - Güínever Eustáquio Império
- 2 Laboratory of Translational Endocrinology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro , Rio de Janeiro, Brazil
| | - Marianna Wilieman
- 1 Laboratory of Molecular Endocrinology, Federal University of Rio de Janeiro , Rio de Janeiro, Brazil
| | | | - Luana Lopes Souza
- 1 Laboratory of Molecular Endocrinology, Federal University of Rio de Janeiro , Rio de Janeiro, Brazil
| | - Isis Hara Trevenzoli
- 1 Laboratory of Molecular Endocrinology, Federal University of Rio de Janeiro , Rio de Janeiro, Brazil
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Stornelli MC, García Mitacek MC, Praderio RG, Nuñez Favre R, de la Sota RL, Stornelli MA. Prolactin, Androstenedione and IGF1 Serum Concentrations During Induced Follicular Growth by eCG Administration in the Bitch. Reprod Domest Anim 2015; 51:130-4. [PMID: 26695709 DOI: 10.1111/rda.12656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022]
Abstract
The oestrus cycle in the domestic bitch, a monoestrous species, differs considerably from that of other veterinary domestic animals species. In the bitch the combined use of eCG and hCG is effective to induce oestrus predictably and safely (Stornelli et al., Theriogenology, 78, 2012 and 1056). Although several studies were done to describe the hormonal changes during the canine oestrus cycle, to our knowledge none was done to describe the hormonal changes during induced follicular growth after the administration of eCG. The aim of this work was to study prolactin (PRL), insulin-like growth factor (IGF1) and androstenedione (ANDR) serum concentrations during follicular growth induced by a single dose of eCG administered to late anoestrous bitches. PRL and ANDR concentrations were lower before than after eCG TRT (before eCG vs pro-oestrus, oestrus and dioestrus; 4.3 ± 1.8 ng/ml vs 6.5 ± 1.6 ng/ml, p < 0.05; 0.08 ± 0.2 ng/ml vs 0.42 ± 0.16 ng/ml, p < 0.05). Conversely, IGF1 concentrations were similar before and after eCG TRT (286.0 ng/ml ±32.2, p > 0.53). Additionally, PRL concentrations were similar before oestrus compared to during oestrus and dioestrus (6.9 ± 1.7 ng/ml, p > 0.19). Furthermore, IGF1 concentrations were higher before and during oestrus compared to first day of dioestrus (286.1 ± 29.8vs 200.4 ± 29.2 ng/ml, p < 0.01). On the contrary, ANDR concentrations were lower before and during oestrus compared to first day of diestrum (0.35 ± 0.17 ng/ml and 0.38 ± 0.15 vs 0.68 ± 0.17 ng/ml, p < 0.05). These results show that treatment with a single injection of 50 IU/kg of eCG in late anoestrous bitches successfully induced changes in follicular growth which were paralleled with changes in PRL, IGF1 and ANDR serum concentration similar to those occurring during a normally occurring oestrous cycle. In addition, our results suggest that IGF1 in the bitch could play an important role in ovarian folliculogenesis.
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Affiliation(s)
- M C Stornelli
- Catedra y Servicio de Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina
| | - M C García Mitacek
- Catedra y Servicio de Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina.,CONICET, Capital Federal, Argentina
| | - R G Praderio
- Catedra y Servicio de Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina.,CONICET, Capital Federal, Argentina
| | - R Nuñez Favre
- Catedra y Servicio de Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina.,CONICET, Capital Federal, Argentina
| | - R L de la Sota
- Catedra y Servicio de Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina.,CONICET, Capital Federal, Argentina
| | - M A Stornelli
- Catedra y Servicio de Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina
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Gelbke HP, Banton M, Leibold E, Pemberton M, Samson SL. A critical review finds styrene lacks direct endocrine disruptor activity. Crit Rev Toxicol 2015; 45:727-64. [PMID: 26406562 DOI: 10.3109/10408444.2015.1064091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The European Commission lists styrene (S) as an endocrine disruptor based primarily on reports of increased prolactin (PRL) levels in S-exposed workers. The US Environmental Protection Agency included S in its list of chemicals to be tested for endocrine activity. Therefore, the database of S for potential endocrine activity is assessed. In vitro and in vivo screening studies, as well as non-guideline and guideline investigations in experimental animals indicate that S is not associated with (anti)estrogenic, (anti)androgenic, or thyroid-modulating activity or with an endocrine activity that may be relevant for the environment. Studies in exposed workers have suggested elevated PRL levels that have been further examined in a series of human and animal investigations. While there is only one definitively known physiological function of PRL, namely stimulation of milk production, many normal stress situations may lead to elevations without any chemical exposure. Animal studies on various aspects of dopamine (DA), the PRL-regulating neurotransmitter, in the central nervous system did not give mechanistic explanations on how S may affect PRL levels. Overall, a neuroendocrine disruption of PRL regulation cannot be deduced from a large experimental database. The effects in workers could not consistently be reproduced in experimental animals and the findings in humans represented acute reversible effects clearly below clinical and pathological levels. Therefore, unspecific acute workplace-related stress is proposed as an alternative mode of action for elevated PRL levels in workers.
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Affiliation(s)
| | - Marcy Banton
- b Lyondell Chemical Company , Houston, Texas , USA
| | | | | | - Susan Leanne Samson
- e Division of Endocrinology, Department of Medicine , Baylor College of Medicine , Houston, Texas , USA
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Wolkers CPB, Serra M, Szawka RE, Urbinati EC. The time course of aggressive behaviour in juvenile matrinxã Brycon amazonicus fed with dietary L-tryptophan supplementation. JOURNAL OF FISH BIOLOGY 2014; 84:45-57. [PMID: 24245775 DOI: 10.1111/jfb.12252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Abstract
This study evaluated the influence of dietary L-tryptophan (TRP) supplementation on the time course of aggressive behaviour and on neuroendocrine and hormonal indicators in juvenile matrinxã Brycon amazonicus. Supplementation with TRP promoted a change in the fight pattern at the beginning of an interaction with an intruder, resulting in decreased aggressive behaviours during the first 20 min. The decrease in aggression did not persist throughout the interaction but increased at 3 and 6 h after the beginning of the fight. Monoamine levels in the hypothalamus were not influenced by TRP before or after the fight; however, the hypothalamic serotonin (5-HT) concentration and the 5-hydroxyindole-3-acetic acid (5HIAA):5-HT ratio were significantly correlated with the reduction in aggressive behaviour at the beginning of the fight. Cortisol was not altered by TRP before the fight. After the fight cortisol increased to higher levels in B. amazonicus fed with supplementary TRP. These results indicate that TRP supplementation alters the aggressive behaviour of B. amazonicus and that this effect is limited to the beginning of the fight, suggesting a transient effect of TRP on aggressive behaviour. This is the first study reporting the effects of TRP supplementation on the time course of aggressive interaction in fishes.
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Affiliation(s)
- C P B Wolkers
- Department of Animal Morphology and Physiology, Faculty of Agriculture and Veterinary Sciences/Aquaculture Center (CAUNESP), Universidade Estadual Paulista, UNESP, Jaboticabal, SP, Brazil
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Cordellini MF, Piazzetta G, Pinto KC, Delattre AM, Matheussi F, Carolino ROG, Szawka RE, Anselmo-Franci JA, Ferraz AC. Effect of Different Doses of Estrogen on the Nigrostriatal Dopaminergic System in Two 6-Hydroxydopamine-Induced Lesion Models of Parkinson’s Disease. Neurochem Res 2011; 36:955-61. [DOI: 10.1007/s11064-011-0428-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2011] [Indexed: 01/03/2023]
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Szawka RE, Ribeiro AB, Leite CM, Helena CVV, Franci CR, Anderson GM, Hoffman GE, Anselmo-Franci JA. Kisspeptin regulates prolactin release through hypothalamic dopaminergic neurons. Endocrinology 2010; 151:3247-57. [PMID: 20410200 DOI: 10.1210/en.2009-1414] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prolactin (PRL) is tonically inhibited by dopamine (DA) released from neurons in the arcuate and periventricular nuclei. Kisspeptin plays a pivotal role in LH regulation. In rodents, kisspeptin neurons are found mostly in the anteroventral periventricular and arcuate nuclei, but the physiology of arcuate kisspeptin neurons is not completely understood. We investigated the role of kisspeptin in the control of hypothalamic DA and pituitary PRL secretion in adult rats. Intracerebroventricular kisspeptin-10 (Kp-10) elicited PRL release in a dose-dependent manner in estradiol (E2)-treated ovariectomized rats (OVX+E2), whereas no effect was found in oil-treated ovariectomized rats (OVX). Kp-10 increased PRL release in males and proestrous but not diestrous females. Associated with the increase in PRL release, intracerebroventricular Kp-10 reduced Fos-related antigen expression in tyrosine hydroxylase-immunoreactive (ir) neurons of arcuate and periventricular nuclei in OVX+E2 rats, with no effect in OVX rats. Kp-10 also decreased 3,4-dihydroxyphenylacetic acid concentration and 3,4-dihydroxyphenylacetic acid-DA ratio in the median eminence but not striatum in OVX+E2 rats. Double-label immunofluorescence combined with confocal microscopy revealed kisspeptin-ir fibers in close apposition to and in contact with tyrosine hydroxylase-ir perikarya in the arcuate. In addition, Kp-10 was not found to alter PRL release from anterior pituitary cell cultures regardless of E2 treatment. We provide herein evidence that kisspeptin regulates PRL release through inhibition of hypothalamic dopaminergic neurons, and that this mechanism is E2 dependent in females. These findings suggest a new role for central kisspeptin with possible implications for reproductive physiology.
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Affiliation(s)
- Raphael E Szawka
- Laboratório de Neuroendocrinologia, Departamento de Morfologia, Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirão Preto, 14040-904.
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de Souza Moreno V, Bícego KC, Szawka RE, Anselmo-Franci JA, Gargaglioni LH. Serotonergic mechanisms on breathing modulation in the rat locus coeruleus. Pflugers Arch 2009; 459:357-68. [DOI: 10.1007/s00424-009-0741-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 09/15/2009] [Accepted: 09/22/2009] [Indexed: 10/20/2022]
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Helena CVV, Szawka RE, Anselmo-Franci JA. Noradrenaline involvement in the negative-feedback effects of ovarian steroids on luteinising hormone secretion. J Neuroendocrinol 2009; 21:805-12. [PMID: 19686440 DOI: 10.1111/j.1365-2826.2009.01907.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Noradrenaline has been shown to modulate the ovarian-steroid feedback on luteinising-hormone (LH) release. However, despite the high amount of evidence accumulated over many years, the role of noradrenaline in LH regulation is still not clearly understood. The present study aimed to further investigate the involvement of noradrenaline in the negative-feedback effect of oestradiol and progesterone on basal LH secretion. In experiment 1, ovariectomised (OVX) rats received a single injection of oil, oestradiol, or progesterone at 09.00-10.00 h and were decapitated 30 or 60 min later. Levels of noradrenaline and its metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG), were determined in microdissections of the preoptic area (POA) and medial basal hypothalamus-median eminence (MBH-ME) and correlated with LH secretion. Basal LH levels were decreased 30 and 60 min after oestradiol or progesterone injection, and this hormonal response was significantly correlated with a reduction in POA MHPG levels, which reflect noradrenaline release. In addition, noradrenaline levels in the POA were increased, whereas noradrenaline turnover (MHPG/noradrenaline ratio) was decreased 60 min after the injection of both hormones. No effect was found in the MBH-ME. In experiment 2, i.c.v. administration of noradrenaline (60 nmol), performed 15 min before oestradiol or progesterone injection in jugular vein-cannulated OVX rats, completely prevented the ovarian steroid-induced inhibition of LH secretion. The data obtained provide direct evidence that LH secretion in OVX rats is positively regulated by basal noradrenergic activity in the POA, and its reduction appears to play a role in the negative-feedback effect of ovarian steroids on LH secretion in vivo.
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Affiliation(s)
- C V V Helena
- Laboratório de Neuroendocrinologia, Departamento de Morfologia Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Machado RB, Tufik S, Suchecki D. Chronic stress during paradoxical sleep deprivation increases paradoxical sleep rebound: association with prolactin plasma levels and brain serotonin content. Psychoneuroendocrinology 2008; 33:1211-24. [PMID: 18674865 DOI: 10.1016/j.psyneuen.2008.06.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Revised: 06/06/2008] [Accepted: 06/19/2008] [Indexed: 11/18/2022]
Abstract
Previous studies suggest that stress associated to sleep deprivation methods can affect the expression of sleep rebound. In order to examine this association and possible mechanisms, rats were exposed to footshock stress during or immediately after a 96-h period of paradoxical sleep deprivation (PSD) and their sleep and heart rate were recorded. Control rats (maintained in individual home cages) and paradoxical sleep-deprived (PS-deprived) rats were distributed in three conditions (1) no footshock--NF; (2) single footshock--SFS: one single footshock session at the end of the PSD period (6-8 shocks per minute; 100 ms; 2 mA; for 40 min); and (3) multiple footshock--MFS: footshock sessions with the same characteristics as described above, twice a day throughout PSD (at 7:00 h and 19:00 h) and one extra session before the recovery period. After PSD, animals were allowed to sleep freely for 72 h. Additional groups were sacrificed at the end of the sleep deprivation period for blood sampling (ACTH, corticosterone, prolactin and catecholamine levels) and brain harvesting (monoamines and metabolites). Neither SFS nor MFS produced significant alterations in the sleep patterns of control rats. All PS-deprived groups exhibited increased heart rate which could be explained by increased dopaminergic activity in the medulla. As expected, PS deprivation induced rebound of paradoxical sleep in the first day of recovery; however, PSD+MFS group showed the highest rebound (327.3% above the baseline). This group also showed intermediate levels of corticosterone and the highest levels of prolactin, which were positively correlated with the length of PS episodes. Moreover, paradoxical sleep deprivation resulted in elevation of the serotonergic turnover in the hypothalamus, which partly explained the hormonal results, and in the hippocampus, which appears to be related to adaptive responses to stress. The data are discussed in the realm of a prospective importance of paradoxical sleep for processing of traumatic events.
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Bibliography. Current world literature. Diabetes and the endocrine pancreas II. Curr Opin Endocrinol Diabetes Obes 2008; 15:383-93. [PMID: 18594281 DOI: 10.1097/med.0b013e32830c6b8e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Leite CM, Szawka RE, Anselmo-Franci JA. Alpha-oestrogen and progestin receptor expression in the hypothalamus and preoptic area dopaminergic neurones during oestrous in cycling rats. J Neuroendocrinol 2008; 20:110-9. [PMID: 18081559 DOI: 10.1111/j.1365-2826.2007.01624.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A secretory surge of prolactin occurs on the afternoon of oestrous in cycling rats. Although prolactin is regulated by ovarian steroids, plasma oestradiol and progesterone levels do not vary during oestrous. Because prolactin release is tonically inhibited by hypothalamic dopamine and modulated by dopamine transmission in the preoptic area (POA), the present study aimed to evaluate whether oestrogen receptor (ER)-alpha and progestin receptor (PR) expression in the dopaminergic neurones of arcuate (ARC), periventricular, anteroventral periventricular (AVPe) and ventromedial preoptic (VMPO) nuclei changes during the day of oestrous. Cycling rats were perfused every 2 h from 10-20 h on oestrous. Brain sections were double-labelled to ERalpha or PR and tyrosine hydroxylase (TH). The number of TH-immunoreactive (ir) neurones did not vary significantly in any area evaluated. ERalpha expression in TH-ir neurones increased at 14 and 16 h in the rostral-ARC and dorsomedial-ARC, 14 h in the caudal-ARC and 16 h in the VMPO, whereas it was unaltered in the ventrolateral-ARC, periventricular and AVPe. PR expression in TH-ir neurones of the periventricular and rostral, dorsomedial, ventrolateral and caudal-ARC decreased transitorily during the afternoon, showing the lowest levels between 14 and 16 h; but it did not vary in the AVPe and VMPO. Plasma oestradiol and progesterone concentrations were low and unaltered during oestrous, indicating that the changes in receptors expression were probably not due to variation in ligand levels. Thus, our data suggest that variations in ERalpha and PR expression may promote changes in the activity of medial basal hypothalamus and POA dopaminergic neurones, even under unaltered secretion of ovarian steroids, which could facilitate the occurrence and modulate the magnitude of the prolactin surge on oestrous.
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Affiliation(s)
- C M Leite
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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