Long‐lasting effects of serotonin deficiency on differentiating peptidergic neurons in the rat suprachiasmatic nucleus

Mirochnik, V. V.; Bosler, Olivier; Tillet, Yves; Calas, A.; Ugrumov, M. V.

doi:10.1016/j.ijdevneu.2004.07.021

Cited by 17 publications

(6 citation statements)

References 39 publications

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“…The materials of the experimental and control animals were processed under standardized conditions (fixation, sectioning and immunostaining) that made it possible to compare the concentrations of the immunoreactive materials in individual neurons and mRNAs in the whole SON by measuring OD (Smolen 1990). The validity of these techniques has been repeatedly demonstrated in earlier studies (Beltramo et al 1994(Beltramo et al , 1997Abramova et al 2002;Mirochnik et al 2005).…”

Section: Technical Remarksmentioning

confidence: 72%

Vasopressinergic neurons of the supraoptic nucleus in perinatal rats: reaction to osmotic stimulation and its regulation

2010

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Osmotic stimulation (OS) of vasopressin (VP) neurons of the supraoptic nucleus (SON) promotes VP secretion and tyrosine hydroxylase (TH) expression in adult mammals. VP secretion is under a noradrenaline control, whereas the regulation of TH expression remains uncertain. This study was aimed to determine at what period of ontogenesis: (1) VP neurons begin to react to OS by modifying simultaneously VP and TH gene expression and synthesis, (2) the noradrenergic control of VP neurons is established. Rats on the 21st embryonic day (E), third postnatal day (P), P13 were salt loaded or salt loaded and treated with an antagonist (prazosin) or agonist (phenylephrine) of α1-adrenoreceptors. According to our immunocytochemical and in situ hybridization data, OS resulted in an increased amount of VP mRNA in each age group and of VP on E21 and P3. TH gene and synthesis was initially expressed under OS on P3. The number of TH-expressing neurons diminished by threefold in salt loaded rats from P3 to P13. OS combined with prazosin administration resulted in an increased level of VP mRNA on P3 and P13, but not on E21 suggesting the onset of the noradrenaline inhibitory control after birth. OS together with prazosin treatment stimulated TH expression on P3 and P13, whereas phenylephrine provided an opposite effect. Thus, VP neurons begin to react to OS by an increased VP synthesis at the end of fetal life and by the onset of TH expression shortly after birth; the expression of both substances appears to be under the inhibitory control of noradrenaline.

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Section: Technical Remarksmentioning

confidence: 72%

Vasopressinergic neurons of the supraoptic nucleus in perinatal rats: reaction to osmotic stimulation and its regulation

2010

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“…In adulthood, they provide short-term reversible effects on the target neurons or peripheral cells controlling a wide range of functions and maintaining homeostasis. In ontogenesis, the neuron-derived SM control the development of the brain providing long-lasting irreversible so-called morphogenetic or imprinting effects on the target neurons within ''critical'' periods of ontogenesis [21][22][23][24].…”

Section: Conventional Concept Of the Neuroendocrine Regulation In Ontmentioning

confidence: 99%

Developing Brain as an Endocrine Organ: A Paradoxical Reality

Ugrumov

2010

Neurochem Res

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The maintaining of homeostasis in the organism in response to a variable environment is provided by the highly hierarchic neuroendocrine-immune system. The crucial component of this system is the hypothalamus providing the endocrine regulation of key peripheral organs, and the adenohypophysis. In this case, neuron-derived signaling molecules (SM) are delivered to the blood vessels in hypothalamic "neurohaemal organs" lacking the blood-brain barrier (BBB), the posterior lobe of the pituitary and the median eminence. The release of SM to the blood vessels in most other brain regions is prohibited by BBB. According to the conventional concept, the development of the neuroendocrine system in ontogenesis begins with the "maturation" of peripheral endocrine glands which first are self-governed and then operate under the adenohypophysial control. Meantime, the brain maturation is under the control of SM secreted by endocrine glands of the developing organism and coming from the placenta and maternal organism. The hypothalamus is involved in the neuroendocrine regulation only after its full maturation that is followed by the conversion of the opened-looped neuroendocrine system to the closed-looped system as in adulthood. Neurons of the developing brain begin to secrete SM shortly after their origin and long before the establishment of specific interneuronal relations providing initially autocrine and paracrine morphogenetic influence on differentiating target neurons. Taking into account that the brain lacks BBB over this ontogenetic period, we hypothesized that it operates as the multipotent endocrine gland secreting SM to the general circulation and thereby providing the endocrine regulation of peripheral organs and the brain. The term "multipotent" means that the spectrum of the brain-derived circulating SM and their occupancy at the periphery in the developing organism should greatly exceed those in adulthood. In order to test this hypothesis, gonadotropin-releasing hormone (GnRH), dopamine (DA), and serotonin (5-hydroxytryptamine, 5-HT) were chosen as the markers of the presumptive endocrine function of the brain in ontogenesis. According to our data, the concentrations of GnRH, DA, and 5-HT in the rat general circulation during the perinatal period, i.e. before the establishment of BBB, was as high as those in the portal circulation in adulthood. The concentrations of circulating GnRH and DA dropped to almost undetectable level after the development of BBB suggesting their brain origin. This suggestion has been proven by showing an essential decrease of GnRH, DA, and 5-HT concentrations in general circulation of perinatal rats after microsurgical elimination of synthesizing neurons or the inhibition of specific syntheses in the brain before the establishment of BBB. GnRH, DA, and 5-HT apparently as dozens of other brain-derived SM appear to be capable of providing the endocrine influence on their peripheral targets like the adenohypophysis, gonads, kidney, heart, blood vessels, and the brain (endocrine autoregulat...

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“…Recently, the same calcium—protein kinase mechanism of melatonin action on the organization of the rhythm of protein synthesis has been estimated for keratinocytes (Brodsky et al, 2010). Existing data concerning serotonin effects on different events of development (Pronina et al, 2003; Voronezhskaya et al, 2004; Mirochnik et al, 2005) add another interesting perspective to studies of melatonin. What is this developmental factor; is it serotonin as such or melatonin originating from serotonin?…”

Section: Discussionmentioning

confidence: 99%

Melatonin as the most effective organizer of the rhythm of protein synthesis in hepatocytes in vitro and in vivo

Brodsky

Zvezdina

2010

Cell Biology International

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Recent data has extended a large array of melatonin functions by the discovery of melatonin's involvement in the organization and regulation of the rhythm of intracellular protein synthesis. An ultradian rhythm in total protein synthesis has been detected in primary hepatocyte cultures 5 min after addition of 1-5 nM melatonin to the medium. The melatonin effect was mediated via its receptors (as shown in experiments with luzindole), leading to the cell synchronization as well as the mean rate of protein synthesis rate being increased. The chain of processes synchronizing the oscillation of the rate protein synthesis throughout the hepatocyte population includes Ca²+ fluxes {experiments with BAPTA-AM [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (acetomethyl ester)]}. Inhibition of protein kinase activity (experiments with H7) inhibited the synchronizing function of melatonin. Activation of protein kinase activity results in a shift of the protein synthesis oscillation; the effect was the same as melatonin added to the culture medium. In another series of experiments, after melatonin was intraperitoneally injected to rat (0.015-0.020 μg/kg), hepatocytes were isolated and cultures established. A synchronizing effect of melatonin in vivo was detected as early as in the estimates from the direct action of melatonin on cell cultures. In the cultures obtained from old rats provided with melatonin, the amplitude of protein synthesis rhythm was enhanced, i.e. cell-cell interactions were increased, as well as rate of the protein synthesis being enhanced.

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Long‐lasting effects of serotonin deficiency on differentiating peptidergic neurons in the rat suprachiasmatic nucleus

Cited by 17 publications

References 39 publications

Vasopressinergic neurons of the supraoptic nucleus in perinatal rats: reaction to osmotic stimulation and its regulation

Vasopressinergic neurons of the supraoptic nucleus in perinatal rats: reaction to osmotic stimulation and its regulation

Developing Brain as an Endocrine Organ: A Paradoxical Reality

Melatonin as the most effective organizer of the rhythm of protein synthesis in hepatocytes in vitro and in vivo

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