Prolactin secretion and its dopamine inhibitory control in rat fetuses

Melnikova, V. I.; Orosco, M.; Rouch, Claude; Calas, A.; Nicolaı̈dis, Stylianos; Ev, Proshlyakova; Sapronova, A. Ya.; Ugrumov, M. V.

doi:10.1530/eje.0.1390337

Cited by 32 publications

(21 citation statements)

References 26 publications

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“…Dopamine is the main inotropic pharmacological agent used to support blood pressure in neonates, and it is likely that it has a similar function physiologically. DA within the brain regulates the proliferation of neuron progenitor cells [24], but the delineation of roles for circulating DA in the fetus have, as yet, been limited to the regulation of pituitary prolactin secretion [25], and to the control of the development of cardiomyocytes, and renal tubular epithelial cells [26,27].…”

Section: Discussionmentioning

confidence: 99%

Arterio-venous differences in cord levels of catecholamines, glucose, lactate and blood gases

Koh

Hume

Eisenhofer

et al. 2016

Journal of Perinatal Medicine

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Background: Norepinephrine (NE) and epinephrine (EPI) levels are higher in cord arterial blood relative to venous blood, consistent with active mechanisms of placentalmaternal clearance. There are no contemporary studies of cord arteriovenous blood levels of sulfated and nonsulfated catechols. Aim: To assess the arteriovenous differences in cord blood levels of dopamine (DA), the sulfated catecholamines and their sulfated and non-sulfated metabolites. To correlate levels of oxygen, H + /CO 2 , and glucose with cord catecholamine levels. Methods: Fifty-seven term infants, delivered by elective cesarean section, were recruited. Cord arterial and venous blood was sampled; levels of glucose, lactate, blood gases, six catechols and their sulfated conjugates were measured. Results: With one exception (DOPA sulfate), mean cord arterial levels of sulfated and non-sulfated catechols were significantly higher than venous levels. Arterial lactate and glucose levels were independently associated with NE levels, but only lactate was associated with levels of EPI and DA. Conclusion: This study establishes that in vivo metabolic parameters of hypoxia, respiratory and metabolic acidosis are associated with catecholamine levels, a key relationship for perinatal adaptation and homeostasis, and findings that are consistent with in vitro studies of the regulators of catecholamine secretion.

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Section: Discussionmentioning

confidence: 99%

Arterio-venous differences in cord levels of catecholamines, glucose, lactate and blood gases

Koh

Hume

Eisenhofer

et al. 2016

Journal of Perinatal Medicine

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“…These data were obtained with high-performance liquid chromatography with electrochemical detection when studying either the mediobasal hypothalamus, dissected at E21, or the primary cell culture of this region taken at E17 and maintained for 7 days . Furthermore, dopamine production in the rat arcuate nucleus at E21 was sufficient to exert an inhibitory control of adenohypophysial prolactin secretion in fetuses (Melnikova et al, 1998), as in adults (Moore et al, 1985). Taking together the data obtained in this study and in our recent studies (Melnikova et al, 1998Balan et al, 2000), it may be suggested that dopamine is synthesized in the arcuate nucleus of fetuses by nondopaminergic TH-or AADCpossessing neurons acting in concert .…”

Section: Ontogenic Trend In the Neuron Populations Possessing Dopaminmentioning

confidence: 99%

“…Furthermore, dopamine production in the rat arcuate nucleus at E21 was sufficient to exert an inhibitory control of adenohypophysial prolactin secretion in fetuses (Melnikova et al, 1998), as in adults (Moore et al, 1985). Taking together the data obtained in this study and in our recent studies (Melnikova et al, 1998Balan et al, 2000), it may be suggested that dopamine is synthesized in the arcuate nucleus of fetuses by nondopaminergic TH-or AADCpossessing neurons acting in concert . Namely, L-tyrosine is converted to L-dopa (Yoshida et al, 1963;Garcia-Sancho et al, 1975;Zoli et al, 1993;Vieira-Coelho and Soares-da-Silva, 1998).…”

Section: Ontogenic Trend In the Neuron Populations Possessing Dopaminmentioning

confidence: 99%

Differentiation of tyrosine hydroxylase‐synthesizing and/or aromatic L‐amino acid decarboxylase‐synthesizing neurons in the rat mediobasal hypothalamus: Quantitative double‐immunofluorescence study

Ершов

Ugrumov

Calas³

et al. 2002

J of Comparative Neurology

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In this double-immunofluorescence study, we first quantified the neurons of the arcuate nucleus as immunoreactive (+) for tyrosine hydroxylase (TH) and/or aromatic L-amino acid decarboxylase (AADC) in rats at embryonic day 21 (E21), at postnatal day 9 (P9), and in adulthood by using conventional fluorescent or confocal microscopy. On E21, monoenzymatic (TH(+)AADC immunonegative (-) and TH(-)AADC(+)) neurons and bienzymatic (TH(+)AADC(+)) neurons accounted for 99% and 1%, respectively, of the whole neuron population expressing enzymes of dopamine synthesis. Further development was characterized by the dramatic increase in TH(+)AADC(-) dorsomedial and TH(+)AADC(+) dorsomedial populations from E21 to P9 as well as by the increase in the TH(+)AADC(+) dorsomedial population (in females) and a drop in the TH(+)AADC(-) ventrolateral and TH(+)AADC(-) dorsomedial (in males) populations from P9 to adulthood. In contrast to TH(+)AADC(-) (in males) and TH(+)AADC(+) neurons, the TH(-)AADC(+) neurons did not change in number from E21 to adulthood. Thus, in rat fetuses, the neurons synthesizing TH and/or AADC were mainly monoenzymatic, whereas during postnatal life the fraction of bienzymatic neurons increased by up to 60%.

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“…Indications for the involvement of dopamine in this regulation in the prenatal period were obtained by inhibiting D2 receptors on lactotropocytes using haloperidol, which led to significant increases in the blood prolactin concentration, accompanied by a decrease in the hypophysis [16]. Regulation manifest as the effect of haloperidol on rat fetuses after initial exclusion of the hypothalamus (because encephalectomy) or hypothalamus and hypophysis (by decapitation) showed that hypothalamic dopamine does indeed affect hypophyseal lactotropocytes.…”

Section: Differentiation Of Hypothalamic Dopaminergic Neurons In Situmentioning

confidence: 99%

The differentiation of dopaminergic neurons in situ, in vivo, and in transplants

Ugryumov

2000

Neurosci Behav Physiol

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This article summarizes results obtained from studies on the differentiation of dopaminergic neurons in animal hypothalamus and human substantia nigra in situ, in vitro, and in transplants, as well as the role of the microenvironment in regulating this process. Four stages were identified in the differentiation of dopaminergic neurons from rat hypothalamus: a) formation of neurons from neuroepithelial precursor cells, b) expression of specific synthetic products (enzymes and dopamine itself) and mechanisms for transmembrane dopamine transport (reuptake and secretion in response to membrane depolarization), c) formation of permanent and transient efferent connections, and d) formation of afferent innervation and synaptogenesis. Along with dopaminergic neurons, rat fetuses contained neurons expressing only one of the dopamine-synthesizing enzymes and probably taking part in in situ dopamine synthesis. Differentiation of dopaminergic neurons was sexually dimorphic in terms of the dynamics of neuron formation and expression of enzymes involved in dopamine synthesis. A neurotransplantation model showed that humoral factors of placental and maternal origin had no significant effect on the differentiation of the dopaminergic neurons of the hypothalamus. As regards the dopaminergic neurons of the substantia nigra, expression of their specific phenotype in human fetuses started with the synthesis of tyrosine hydroxylase and co-maturation of the specific dopamine reuptake mechanism during the sixth week of development. During the next four weeks, specific uptake increased, and this appears to be a measure of the number of neurons and the growth of their processes. These data provide the basis for regarding the period from week 6 to week 10 as optimal for transplantation of dopaminergic neurons into the striatum of patients with Parkinson's disease. Suspensions of fetal substantia nigra cells enriched with dopaminergic neurons were introduced stereotaxically into a patient's striatum through a cannula. Positron emission tomography studies showed that the transplanted neurons survived within the host brain, underwent differentiation, and started to synthesize dopamine. The results of clinical assessment performed in parallel with these studies suggested that the transplanted dopaminergic neurons were involved in regulating striatal target neurons.

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Prolactin secretion and its dopamine inhibitory control in rat fetuses

Cited by 32 publications

References 26 publications

Arterio-venous differences in cord levels of catecholamines, glucose, lactate and blood gases

Arterio-venous differences in cord levels of catecholamines, glucose, lactate and blood gases

Differentiation of tyrosine hydroxylase‐synthesizing and/or aromatic L‐amino acid decarboxylase‐synthesizing neurons in the rat mediobasal hypothalamus: Quantitative double‐immunofluorescence study

The differentiation of dopaminergic neurons in situ, in vivo, and in transplants

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