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Moraes DJ, Bonagamba LG, da Silva MP, Mecawi AS, Antunes-Rodrigues J, Machado BH. Respiratory Network Enhances the Sympathoinhibitory Component of Baroreflex of Rats Submitted to Chronic Intermittent Hypoxia. Hypertension 2016; 68:1021-30. [DOI: 10.1161/hypertensionaha.116.07731] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/09/2016] [Indexed: 11/16/2022]
Abstract
Chronic intermittent hypoxia (CIH) produces respiratory-related sympathetic overactivity and hypertension in rats. In this study, we tested the hypothesis that the enhanced central respiratory modulation of sympathetic activity after CIH also decreases the sympathoinhibitory component of baroreflex of rats, which may contribute to the development of hypertension. Wistar rats were exposed to CIH or normoxia (control group) for 10 days. Phrenic nerve, thoracic sympathetic nerve, and neurons in the rostral ventrolateral medulla and caudal ventrolateral medulla were recorded in in situ preparations of rats. Baroreflex regulation of thoracic sympathetic nerve, rostral ventrolateral medulla, and caudal ventrolateral medulla neurons activities were evaluated in different phases of respiration in response to either aortic depressor nerve stimulation or pressure stimuli. CIH rats presented higher respiratory-related thoracic sympathetic nerve and rostral ventrolateral medulla presympathetic neurons activities at the end of expiration in relation to control rats, which are indexes of respiratory-related sympathetic overactivity. Baroreflex-evoked thoracic sympathetic nerve inhibition during expiration, but not during inspiration, was enhanced in CIH when compared with control rats. In addition, CIH selectively enhanced the expiratory-related baroreceptor inputs, probably through caudal ventrolateral medulla neurons, to the respiratory-modulated bulbospinal rostral ventrolateral medulla presympathetic neurons. These findings support the concept that the onset of hypertension, mediated by sympathetic overactivity, after 10 days of CIH is not secondary to a reduction in sympathoinhibitory component of baroreflex. Instead, it was observed an increase in the gain of sympathoinhibitory component in in situ preparations of rats, suggesting that changes in the respiratory-related sympathetic network after CIH also play a key role in preventing greater increase in arterial pressure.
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Stabile AM, Moreto V, Batalhão ME, Rocha MJ, Antunes-Rodrigues J, Cárnio EC. Differential Role of Neurohypophysial Hormones in Hypotension and Nitric Oxide Production During Endotoxaemia. J Neuroendocrinol 2016; 28. [PMID: 27037598 DOI: 10.1111/jne.12391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/29/2016] [Accepted: 03/30/2016] [Indexed: 11/27/2022]
Abstract
Besides their well-established endocrine roles, vasopressin and oxytocin are also important regulators of immune function, participating in a complex neuroendocrine-immune network. In the present study, we investigated whether and how vasopressin and oxytocin could modulate lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a well-established model of experimental endotoxaemia. Male Wistar rats were previously treated i.v. with vasopressin V1 or oxytocin receptor antagonists and then received either an i.v. LPS injection to induce endotoxaemia or a saline imjection as a control. The animals were divided into two groups: in the first group, blood was collected at 2, 4 and 6 h after LPS injection; in the second group, mean arterial blood pressure (MABP) and heart rate (HR) were recorded over 6 h. Plasma vasopressin and oxytocin values were higher in LPS- compared to saline-injected animals at 2 and 4 h but returned to basal levels at 6 h. NO levels exhibited an opposite pattern, showing a progressive increase over the entire period. The previous administration of a vasopressin V1 receptor antagonist significantly reduced NO plasma concentrations at 2 and 4 h but not at 6 h. By contrast, oxytocin receptor agonist pre-treatment had no effect on the NO plasma concentration. In relation to MABP, previous treatment with vasopressin V1 receptor antagonist reversed the LPS-induced hypotension at 4 h, although this was not the case for oxytocin antagonist-treated animals. None of the antagonists affected HR. Our findings indicate that vasopressin (but not oxytocin) has effects on NO production during endotoxaemia in rats, although they do not lend support to the proposed anti-inflammatory actions of vasopressin during endotoxaemia.
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Domingos-Souza G, Meschiari CA, Buzelle SL, Callera JC, Antunes-Rodrigues J. Sodium and water intake are not affected by GABAC receptor activation in the lateral parabrachial nucleus of sodium-depleted rats. J Chem Neuroanat 2016; 74:47-54. [PMID: 26970564 DOI: 10.1016/j.jchemneu.2016.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 02/13/2016] [Accepted: 03/05/2016] [Indexed: 11/16/2022]
Abstract
The activation of GABAergic receptors, GABAA and GABAB, in the lateral parabrachial nucleus (LPBN) increases water and sodium intake in satiated and fluid-depleted rats. The present study investigated the presence of the GABAC receptor in the LPBN, its involvement in water and sodium intake, and its effects on cardiovascular parameters during the acute fluid depletion induced by furosemide combined with captopril (Furo/Cap). One group of male Wistar rats (290-300g) with bilateral stainless steel LPBN cannulas was used to test the effects of a GABAC receptor agonist and antagonist on the fluid intake and cardiovascular parameters. We investigated the effects of bilateral LPBN injections of trans-4-aminocrotonic acid (TACA) on the intake of water and 0.3M NaCl induced by acute fluid depletion (subcutaneous injection of Furo/Cap). c-Fos expression increased (P<0.05), suggesting LPBN neuronal activation. The injection of different doses of TACA (0.5, 2.0 and 160 nmol) in the LPBN did not change the sodium or water intake in Furo/Cap-treated rats (P>0.05). Treatment with the GABAC receptor antagonist (Z)-3-[(aminoiminomethyl)thio]prop-2-enoic acid sulfate (ZAPA, 10nmol) or with ZAPA (10nmol) plus TACA (160nmol) did not change the sodium or water intake compared with that for vehicle (saline) (P>0.05). Bilateral injections of the GABAC agonist in the LPBN of Furo/Cap-treated rats did not affect the mean arterial pressure (MAP) or heart rate (HR). The GABAC receptor expression in the LPBN was confirmed by the presence of a 50kDa band. Although LPBN neurons might express GABAC receptors, their activation produced no change in water and sodium intake or in the cardiovascular parameters in the acute fluid depletion rats. Therefore, the GABAC receptors in the LPBN might not interfere with fluid and blood pressure regulation.
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Almeida-Pereira G, Coletti R, Mecawi AS, Reis LC, Elias LLK, Antunes-Rodrigues J. Estradiol and angiotensin II crosstalk in hydromineral balance: Role of the ERK1/2 and JNK signaling pathways. Neuroscience 2016; 322:525-38. [PMID: 26951941 DOI: 10.1016/j.neuroscience.2016.02.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/17/2016] [Accepted: 02/28/2016] [Indexed: 10/22/2022]
Abstract
The angiotensin II (ANGII) receptor AT1 plays an important role in the control of hydromineral balance, mediating the dipsogenic and natriorexigenic effects and neuroendocrine responses of ANGII. While estradiol (E2) is known to modulate several actions of ANGII in the brain, the molecular and cellular mechanisms of the interaction between E2 and ANGII and its physiological role in the control of body fluids remain unclear. We investigated the influence of E2 (40 μg/kg) pretreatment and extracellular-signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) cell signaling on the dipsogenic and natriorexigenic effects, as well as the neuroendocrine responses to angiotensinergic central stimulation in ovariectomized rats (OVX). We showed that the inhibitory effect of E2 on ANGII-induced water and sodium intake requires the ERK1/2 and JNK signaling pathways. On the other hand, E2 pretreatment prevents the ANGII-induced phosphorylation of ERK and JNK in the lamina terminalis. E2 therapy decreased oxytocin (OT) and vasopressin (AVP) secretion and decreased ERK1/2 phosphorylation in the supraoptic and paraventricular nuclei (SON and PVN, respectively). We found that the AVP secretion induced by ANGII required ERK1/2 signaling, but OT secretion did not involve ERK1/2 signaling. Taken together, these results demonstrate that E2 modulates ANGII-induced water and sodium intake and AVP secretion by affecting the ERK1/2 and JNK pathways in the lamina terminalis and ERK1/2 signaling in the hypothalamic nuclei (PVN and SON) in OVX rats.
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Vechiato FMV, Rivas PMS, Ruginsk SG, Borges BC, Elias LLK, Antunes-Rodrigues J. The type-1 cannabinoid receptor modulates the hydroelectrolytic balance independently of the energy homeostasis during salt load. Horm Behav 2016; 78:43-51. [PMID: 26497248 DOI: 10.1016/j.yhbeh.2015.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 09/18/2015] [Accepted: 10/20/2015] [Indexed: 01/20/2023]
Abstract
Hydroelectrolytic imbalances, such as saline load (SL), trigger behavioral and neuroendocrine responses, such as thirst, hypophagia, vasopressin (AVP) and oxytocin (OT) release and hypothalamus–pituitary–adrenal (HPA) axis activation. To investigate the participation of the type-1 cannabinoid receptor (CB1R) in these homeostatic mechanisms,male adult Wistar rats were subjected to SL (0.3MNaCl) for four days. SL induced not only increases in the water intake and plasma levels of AVP, OT and corticosterone, as previously described, but also increases in CB1R expression in the lamina terminalis, which integrates sensory afferents, aswell as in the hypothalamus, the main integrative and effector area controlling hydroelectrolytic homeostasis. A more detailed analysis revealed that CB1R-positive terminals are in close apposition with not only axons but also dendrites and secretory granules of magnocellular neurons, particularly vasopressinergic cells. In satiated and euhydrated animals, the intracerebroventricular administration of the CB1R selective agonist ACEA (0.1 μg/5 μL) promoted hyperphagia, but this treatment did not reverse the hyperosmolality-induced hypophagia in the SL group. Furthermore, ACEA pretreatment potentiated water intake in the SL animals during rehydration as well as enhanced the corticosterone release and prevented the increase in AVP and OT secretion induced by SL. The same parameters were not changed by ACEA in the animals whose daily food intake was matched to that of the SL group (Pair-Fed). These data indicate that CB1Rs modulate the hydroelectrolytic balance independently of the food intake during sustained hyperosmolality and hypovolemia.
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Greenwood MP, Greenwood M, Mecawi AS, Antunes-Rodrigues J, Paton JFR, Murphy D. Rasd1, a small G protein with a big role in the hypothalamic response to neuronal activation. Mol Brain 2016; 9:1. [PMID: 26739966 PMCID: PMC4704412 DOI: 10.1186/s13041-015-0182-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/23/2015] [Indexed: 12/28/2022] Open
Abstract
Background Rasd1 is a member of the Ras family of monomeric G proteins that was first identified as a dexamethasone inducible gene in the pituitary corticotroph cell line AtT20. Using microarrays we previously identified increased Rasd1 mRNA expression in the rat supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus in response to increased plasma osmolality provoked by fluid deprivation and salt loading. RASD1 has been shown to inhibit adenylyl cyclase activity in vitro resulting in the inhibition of the cAMP-PKA-CREB signaling pathway. Therefore, we tested the hypothesis that RASD1 may inhibit cAMP stimulated gene expression in the brain. Results We show that Rasd1 is expressed in vasopressin neurons of the PVN and SON, within which mRNA levels are induced by hyperosmotic cues. Dexamethasone treatment of AtT20 cells decreased forskolin stimulation of c-Fos, Nr4a1 and phosphorylated CREB expression, effects that were mimicked by overexpression of Rasd1, and inhibited by knockdown of Rasd1. These effects were dependent upon isoprenylation, as both farnesyltransferase inhibitor FTI-277 and CAAX box deletion prevented Rasd1 inhibition of cAMP-induced gene expression. Injection of lentiviral vector into rat SON expressing Rasd1 diminished, whereas CAAX mutant increased, cAMP inducible genes in response to osmotic stress. Conclusions We have identified two mechanisms of Rasd1 induction in the hypothalamus, one by elevated glucocorticoids in response to stress, and one in response to increased plasma osmolality resulting from osmotic stress. We propose that the abundance of RASD1 in vasopressin expressing neurons, based on its inhibitory actions on CREB phosphorylation, is an important mechanism for controlling the transcriptional responses to stressors in both the PVN and SON. These effects likely occur through modulation of cAMP-PKA-CREB signaling pathway in the brain.
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David RB, Roncari CF, Lauar MR, Vendramini RC, Antunes-Rodrigues J, Menani JV, De Luca LA. Sodium intake, brain c-Fos protein and gastric emptying in cell-dehydrated rats treated with methysergide into the lateral parabrachial nucleus. Physiol Behav 2015; 151:111-20. [DOI: 10.1016/j.physbeh.2015.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 06/11/2015] [Accepted: 07/10/2015] [Indexed: 10/23/2022]
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Pereira CA, Ferreira NS, Mestriner FL, Antunes-Rodrigues J, Evora PR, Resstel LB, Carneiro FS, Tostes RC. Chronic fluoxetine treatment increases NO bioavailability and calcium-sensitive potassium channels activation in rat mesenteric resistance arteries. Eur J Pharmacol 2015; 765:375-83. [DOI: 10.1016/j.ejphar.2015.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 08/26/2015] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
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Dalmasso C, Antunes-Rodrigues J, Vivas L, De Luca LA. Mapping brain Fos immunoreactivity in response to water deprivation and partial rehydration: Influence of sodium intake. Physiol Behav 2015; 151:494-501. [PMID: 26297688 DOI: 10.1016/j.physbeh.2015.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 08/13/2015] [Accepted: 08/14/2015] [Indexed: 12/13/2022]
Abstract
Water deprivation (WD) followed by water intake to satiety, produces satiation of thirst and partial rehydration (PR). Thus, WD-PR is a natural method to differentiate thirst from sodium appetite. WD-PR also produces Fos immunoreactivity (Fos-ir) in interconnected areas of a brain circuit postulated to subserve sodium appetite. In the present work, we evaluated the effect of sodium intake on Fos-ir produced by WD-PR in brain areas operationally defined according to the literature as either facilitatory or inhibitory to sodium intake. Isotonic NaCl was available for ingestion in a sodium appetite test performed immediately after a single episode of WD-PR. Sodium intake decreased Fos-ir in facilitatory areas such as the lamina terminalis (particularly subfornical organ and median preoptic nucleus), central amygdala and hypothalamic parvocellular paraventricular nucleus in the forebrain. Sodium intake also decreased Fos-ir in inhibitory areas such as the area postrema, lateral parabrachial nucleus and nucleus of the solitary tract in the hindbrain. In contrast, sodium intake further increased Fos-ir that was activated by water deprivation in the dorsal raphe nucleus, another inhibitory area localized in the hindbrain. WD-PR increased Fos-ir in the core and shell of the nucleus accumbens. Sodium intake reduced Fos-ir in both parts of the accumbens. In summary, sodium intake following WD-PR reduced Fos-ir in most facilitatory and inhibitory areas, but increased Fos-ir in another inhibitory area. It also reduced Fos-ir in a reward area (accumbens). The results suggest a functional link between sodium intake and the activity of the hindbrain-forebrain circuitry subserving reward and sodium appetite in response to water deprivation.
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Maués LAL, Macchi BM, Crespo-López ME, Nasciutti LE, Picanço-Diniz DLW, Antunes-Rodrigues J, Nascimento JLMD. Methylmercury inhibits prolactin release in a cell line of pituitary origin. ACTA ACUST UNITED AC 2015; 48:691-6. [PMID: 26108095 PMCID: PMC4541687 DOI: 10.1590/1414-431x20154165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 01/15/2015] [Indexed: 11/30/2022]
Abstract
Heavy metals, such as methylmercury, are key environmental pollutants that easily
reach human beings by bioaccumulation through the food chain. Several reports have
demonstrated that endocrine organs, and especially the pituitary gland, are potential
targets for mercury accumulation; however, the effects on the regulation of hormonal
release are unclear. It has been suggested that serum prolactin could represent a
biomarker of heavy metal exposure. The aim of this study was to evaluate the effect
of methylmercury on prolactin release and the role of the nitrergic system using
prolactin secretory cells (the mammosomatotroph cell line, GH3B6). Exposure to
methylmercury (0-100 μM) was cytotoxic in a time- and concentration-dependent manner,
with an LC50 higher than described for cells of neuronal origin,
suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low
as 1 μM for 2 h) also decreased prolactin release. Interestingly, inhibition of
nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in
prolactin release without acute neurotoxic effects of methylmercury. These data
indicate that the decrease in prolactin production occurs via activation of the
nitrergic system and is an early effect of methylmercury in cells of pituitary
origin.
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Margatho L, Porcari C, Macchione A, da Silva Souza G, Caeiro X, Antunes-Rodrigues J, Vivas L, Godino A. Temporal dissociation between sodium depletion and sodium appetite appearance: Involvement of inhibitory and stimulatory signals. Neuroscience 2015; 297:78-88. [DOI: 10.1016/j.neuroscience.2015.03.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/20/2015] [Accepted: 03/25/2015] [Indexed: 12/23/2022]
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Passaglia P, Ceron CS, Mecawi AS, Antunes-Rodrigues J, Coelho EB, Tirapelli CR. Angiotensin type 1 receptor mediates chronic ethanol consumption-induced hypertension and vascular oxidative stress. Vascul Pharmacol 2015; 74:49-59. [PMID: 25872164 DOI: 10.1016/j.vph.2015.04.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 03/09/2015] [Accepted: 04/04/2015] [Indexed: 02/06/2023]
Abstract
OBJECTIVES We hypothesized that chronic ethanol intake enhances vascular oxidative stress and induces hypertension through renin-angiotensin system (RAS) activation. METHODS AND RESULTS Male Wistar rats were treated with ethanol (20% v/v). The increase in blood pressure induced by ethanol was prevented by losartan (10mg/kg/day; p.o. gavage), a selective AT1 receptor antagonist. Chronic ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels and serum aldosterone levels. No differences on plasma osmolality and sodium or potassium levels were detected after treatment with ethanol. Ethanol consumption did not alter ACE activity, as well as the levels of ANG I and ANG II in the rat aorta or mesenteric arterial bed (MAB). Ethanol induced systemic and vascular oxidative stress (aorta and MAB) and these effects were prevented by losartan. The decrease on plasma and vascular nitrate/nitrite (NOx) levels induced by ethanol was prevented by losartan. Ethanol intake did not alter protein expression of ACE, AT1 or AT2 receptors in both aorta and MAB. Aortas from ethanol-treated rats displayed decreased ERK1/2 phosphorylation and increased protein expression of SAPK/JNK. These responses were prevented by losartan. MAB from ethanol-treated rats displayed reduced phosphorylation of p38MAPK and ERK1/2 and losartan did not prevent these responses. CONCLUSIONS Our study provides novel evidence that chronic ethanol intake increases blood pressure, induces vascular oxidative stress and decreases nitric oxide (NO) bioavailability through AT1-dependent mechanisms.
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Soares RO, Rorato RC, Padovan D, Lachat JJ, Antunes-Rodrigues J, Elias LL, Almeida SS. Environmental enrichment reverses reduction in glucocorticoid receptor expression in the hippocampus of and improves behavioral responses of anxiety in early malnourished rats. Brain Res 2015; 1600:32-41. [DOI: 10.1016/j.brainres.2014.12.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 12/01/2014] [Accepted: 12/20/2014] [Indexed: 01/07/2023]
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Reis WL, Biancardi VC, Son S, Antunes-Rodrigues J, Stern JE. Carbon monoxide and nitric oxide interactions in magnocellular neurosecretory neurones during water deprivation. J Neuroendocrinol 2015; 27:111-22. [PMID: 25494574 DOI: 10.1111/jne.12245] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 11/13/2014] [Accepted: 12/07/2014] [Indexed: 12/21/2022]
Abstract
Nitric oxide (NO) and carbon monoxide (CO) are diffusible gas messengers in the brain. Previously, we have shown their independent involvement in central fluid/electrolyte homeostasis control. In the present study, we investigated a possible functional interaction between NO/CO in the regulation of vasopressin (VP) and oxytocin (OT) magnocellular neurosecretory cells (MNCs) activity in euhydrated (EU) and dehydrated [48-h water-deprived (48WD)] rats. Using brain slices from EU and 48WD rats, we measured, by immunohistochemistry, the expression of neuronal NO synthase (nNOS, which synthesises NO) and haeme-oxygenase (HO-1, which synthesises CO) in the hypothalamic supraoptic nucleus (SON). In addition, we used patch-clamp electrophysiology to investigate whether regulation of SON MNC firing activity by endogenous CO was dependent on NO bioavailability and GABAergic inhibitory synaptic function. We found a proportion of OT and VP SON MNCs in EU rats to co-express both of HO-1 and nNOS (33.2 ± 2.9% and 15.3 ± 1.4%, respectively), which was increased in 48WD rats (55.5 ± 0.9% and 21.0 ± 1.7%, respectively, P < 0.05 for both). Inhibition of endogenous HO activity [chromium mesoporphyrin IX chloride (CrMP) 20 μm] induced MNC membrane hyperpolarisation and decreased firing activity, and these effects were blunted by previous blockade of endogenous NOS activity (l-NAME, 2 mm) or blockade of inhibitory GABA function [Picrotoxin (Sigma-Aldrich, St Louis, MO, USA), 50 μm]. No significant changes in SON NO bioavailability (4,5 diaminofluorescein diacetate fluorescence) were observed after CrMP treatment. Taken together, our results support a state-dependent functional inter-relationship between NO and CO in MNCs, in which CO acts as an excitatory gas molecule, whose effects are largely dependent on interactions with the inhibitory SON signals NO and GABA.
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Gonzaga NA, Mecawi AS, Antunes-Rodrigues J, De Martinis BS, Padovan CM, Tirapelli CR. Ethanol withdrawal increases oxidative stress and reduces nitric oxide bioavailability in the vasculature of rats. Alcohol 2015; 49:47-56. [PMID: 25557835 DOI: 10.1016/j.alcohol.2014.12.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 10/31/2014] [Accepted: 12/04/2014] [Indexed: 01/17/2023]
Abstract
We analyzed the effects of ethanol withdrawal on the vascular and systemic renin-angiotensin system (RAS) and vascular oxidative stress. Male Wistar rats were treated with ethanol 3-9% (v/v) for a period of 21 days. Ethanol withdrawal was induced by abrupt discontinuation of the treatment. Experiments were performed 48 h after ethanol discontinuation. Rats from the ethanol withdrawal group showed decreased exploration of the open arms of the elevated-plus maze (EPM) and increased plasma corticosterone levels. Ethanol withdrawal significantly increased systolic blood pressure and plasma angiotensin II (ANG II) levels without an effect on plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, or plasma angiotensin I (ANG I) levels. No differences in vascular ANG I, ANG II levels, and ACE activity/expression and AT1 and AT2 receptor expression were detected among the experimental groups. Plasma osmolality, as well as plasma sodium, potassium, and glucose levels were not affected by ethanol withdrawal. Ethanol withdrawal induced systemic and vascular oxidative stress, as evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels and the vascular generation of superoxide anion. Ethanol withdrawal significantly decreased plasma and vascular nitrate/nitrite levels. Major new findings of the present study are that ethanol withdrawal induces vascular oxidative stress and reduces nitric oxide (NO) levels in the vasculature. Additionally, our study provides novel evidence that ethanol withdrawal does not affect the vascular ANG II generating system while stimulating systemic RAS. These responses could predispose individuals to the development of cardiovascular diseases.
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Coletti R, Almeida-Pereira G, Elias LLK, Antunes-Rodrigues J. Effects of hydrogen sulfide (H2S) on water intake and vasopressin and oxytocin secretion induced by fluid deprivation. Horm Behav 2015; 67:12-20. [PMID: 25436932 DOI: 10.1016/j.yhbeh.2014.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 10/10/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022]
Abstract
During dehydration, responses of endocrine and autonomic control systems are triggered by central and peripheral osmoreceptors and peripheral baroreceptors to stimulate thirst and sodium appetite. Specifically, it is already clear that endocrine system acts by secreting vasopressin (AVP), oxytocin (OT) and angiotensin II (ANG II), and that gaseous molecules, such as nitric oxide (NO) and carbon monoxide (CO), play an important role in modulating the neurohypophyseal secretion as well as ANG II production and thirst. More recently, another gas-hydrogen sulfide (H2S)-has been studied as a neuronal modulator, which is involved in hypothalamic control of blood pressure, heart frequency and temperature. In this study, we aimed to investigate whether H2S and its interaction with NO system could participate in the modulatory responses of thirst and hormonal secretion induced by fluid deprivation. For this purpose, Wistar male rats were deprived of water for 12 and 24h, and the activity of sulfide-generating enzymes was measured. Surprisingly, 24-h water deprivation increased the activity of sulfide-generating enzymes in the medial basal hypothalamus (MBH). Furthermore, the icv injection of sodium sulfide (Na2S, 260nmol), a H2S donor, reduced water intake, increased AVP, OT and CORT plasma concentrations and decreased MBH nitrate/nitrite (NOX) content of 24-h water-deprived animals compared to controls. We thus suggest that H2S system has an important role in the modulation of hormonal and behavioral responses induced by 24-h fluid deprivation.
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Carda APP, Marchi KC, Rizzi E, Mecawi AS, Antunes-Rodrigues J, Padovan CM, Tirapelli CR. Acute restraint stress induces endothelial dysfunction: role of vasoconstrictor prostanoids and oxidative stress. Stress 2015; 18:233-43. [PMID: 25689973 DOI: 10.3109/10253890.2015.1014790] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We hypothesized that acute stress would induce endothelial dysfunction. Male Wistar rats were restrained for 2 h within wire mesh. Functional and biochemical analyses were conducted 24 h after the 2-h period of restraint. Stressed rats showed decreased exploration on the open arms of an elevated-plus maze (EPM) and increased plasma corticosterone concentration. Acute restraint stress did not alter systolic blood pressure, whereas it increased the in vitro contractile response to phenylephrine and serotonin in endothelium-intact rat aortas. NG-nitro-l-arginine methyl ester (l-NAME; nitric oxide synthase, NOS, inhibitor) did not alter the contraction induced by phenylephrine in aortic rings from stressed rats. Tiron, indomethacin and SQ29548 reversed the increase in the contractile response to phenylephrine induced by restraint stress. Increased systemic and vascular oxidative stress was evident in stressed rats. Restraint stress decreased plasma and vascular nitrate/nitrite (NOx) concentration and increased aortic expression of inducible (i) NOS, but not endothelial (e) NOS. Reduced expression of cyclooxygenase (COX)-1, but not COX-2, was observed in aortas from stressed rats. Restraint stress increased thromboxane (TX)B(2) (stable TXA(2) metabolite) concentration but did not affect prostaglandin (PG)F2α concentration in the aorta. Restraint reduced superoxide dismutase (SOD) activity, whereas concentrations of hydrogen peroxide (H(2)O(2)) and reduced glutathione (GSH) were not affected. The major new finding of our study is that restraint stress increases vascular contraction by an endothelium-dependent mechanism that involves increased oxidative stress and the generation of COX-derived vasoconstrictor prostanoids. Such stress-induced endothelial dysfunction could predispose to the development of cardiovascular diseases.
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MESH Headings
- 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt/pharmacology
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Aorta/physiopathology
- Blood Pressure/drug effects
- Bridged Bicyclo Compounds, Heterocyclic
- Cyclooxygenase 1/metabolism
- Cyclooxygenase 2/metabolism
- Cyclooxygenase Inhibitors/pharmacology
- Dinoprost/metabolism
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Fatty Acids, Unsaturated
- Glutathione/metabolism
- Hydrazines/pharmacology
- Hydrogen Peroxide/metabolism
- Indomethacin/pharmacology
- Male
- Membrane Proteins/metabolism
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide Synthase/metabolism
- Oxidative Stress/drug effects
- Oxidative Stress/physiology
- Phenylephrine/pharmacology
- Prostaglandins
- Rats
- Rats, Wistar
- Restraint, Physical
- Serotonin/pharmacology
- Stress, Psychological/metabolism
- Stress, Psychological/physiopathology
- Thiobarbituric Acid Reactive Substances/metabolism
- Thromboxane B2/metabolism
- Vasoconstrictor Agents/pharmacology
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68
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Marangon PB, Silva LECM, Rorato R, Gomiero Alves P, Antunes-Rodrigues J, Elias LLK. Oestradiol modulates the effects of leptin on energy homeostasis by corticotrophin-releasing factor type 2 receptor. J Neuroendocrinol 2014; 26:796-804. [PMID: 25113140 DOI: 10.1111/jne.12192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/30/2014] [Accepted: 08/06/2014] [Indexed: 11/28/2022]
Abstract
In addition to its action in the control of the hypothalamic-pituitary-adrenal axis, corticotrophin-releasing factor (CRF) has been described as an anorexigenic neuropeptide, modulating food intake and energy expenditure. CRF synthesis is influenced by leptin, which would act to increase CRF neurone activation in the paraventricular nucleus (PVN). Gonadal hormones also participate in the regulation of energy homeostasis. The reduction of food intake and body weight gain in ovariectomised (OVX) rats treated with oestradiol is associated with an increase in CRF mRNA expression in the PVN. The present study aimed to investigate the role of CRF as a mediator of leptin responsiveness in the presence of oestradiol. Wistar female rats were bilaterally OVX and divided into three groups: OVX, OVX+E (i.e. treated with oestradiol) and OVX+PF (i.e. OVX pairfed with OVX+E). The rats received daily s.c. injections of either oestradiol cypionate or vehicle for 8 days. To evaluate the role of CRF on the effects of leptin, we performed an i.c.v. leptin injection (10 μg/5 μl) with or without previous i.c.v. treatment with an CRF-R2 antagonist. We observed that oestradiol replacement in OVX rats reduced body weight gain and food intake. The effects of exogenous leptin administration with respect to decreasing food intake and body weight, and increasing uncoupling protein-1 expression in the brown adipose tissue and neuronal activation in the arcuate nucleus, were reversed by previous administration of a CRF-R2 antagonist only in oestradiol-treated OVX rats. These effects appear to be mediated by CRF-2 receptor because the antagonist of this receptor reversed the action of oestradiol on the effects of leptin.
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69
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Crestani CC, Lopes da Silva A, Scopinho AA, Ruginsk SG, Uchoa ET, Correa FM, Elias LL, Antunes-Rodrigues J, Resstel LB. Cardiovascular alterations at different stages of hypertension development during ethanol consumption: Time-course of vascular and autonomic changes. Toxicol Appl Pharmacol 2014; 280:245-55. [DOI: 10.1016/j.taap.2014.08.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 07/19/2014] [Accepted: 08/13/2014] [Indexed: 12/18/2022]
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70
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Ruginsk SG, Vechiato FMV, Elias LLK, Antunes-Rodrigues J. The endocannabinoid system and the neuroendocrine control of hydromineral balance. J Neuroendocrinol 2014; 26:370-6. [PMID: 24750469 DOI: 10.1111/jne.12158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/06/2014] [Accepted: 04/12/2014] [Indexed: 12/25/2022]
Abstract
Endocannabinoids (ECBs) are ubiquitous lipophilic agents, and this characteristic is consistent with the wide range of homeostatic functions attributed to the ECB system. There is an increasing number of studies showing that the ECB system affects neurotransmission within the hypothalamic neurohypophyseal system. We provide an overview of the primary roles of ECBs in the modulation of neuroendocrine function and, specifically, in the control of hydromineral homeostasis. Accordingly, the general aspects of ECB-mediated signalling, as well as the specific contributions of the central component of the ECB system to the integration of behavioural and endocrine responses that control body fluid homeostasis, are discussed.
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71
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Gonzaga NA, Callera GE, Yogi A, Mecawi AS, Antunes-Rodrigues J, Queiroz RH, Touyz RM, Tirapelli CR. Acute ethanol intake induces mitogen-activated protein kinase activation, platelet-derived growth factor receptor phosphorylation, and oxidative stress in resistance arteries. J Physiol Biochem 2014; 70:509-23. [PMID: 24733165 DOI: 10.1007/s13105-014-0331-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 03/10/2014] [Indexed: 12/16/2022]
Abstract
In the present study, we investigated the role of angiotensin type I (AT1) receptor in reactive oxygen species (ROS) generation and mitogen-activated protein kinases (MAPK) activation induced by acute ethanol intake in resistance arteries. We also evaluated the effect of ethanol on platelet-derived growth factor receptors (PDGF-R) phosphorylation and the role of this receptor on ROS generation by ethanol. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. Acute ethanol intake did not alter angiotensin I or angiotensin II levels in the rat mesenteric arterial bed (MAB). Ethanol induced vascular oxidative stress, and this response was not prevented by losartan (10 mg/kg; p.o. gavage), a selective AT1 receptor antagonist. MAB from ethanol-treated rats displayed increased SAPK/JNK and PDGF-R phosphorylation, responses that were not prevented by losartan. The phosphorylation levels of protein kinase B (Akt) and eNOS were not affected by acute ethanol intake. MAB nitrate levels and the reactivity of this tissue to acetylcholine, phenylephrine, and sodium nitroprusside were not affected by ethanol intake. Ethanol did not alter plasma antioxidant capacity, the levels of reduced glutathione, or the activities of superoxide dismutase and catalase in the rat MAB. Short-term effects of ethanol (50 mmol/l) were evaluated in vascular smooth muscle cells (VSMC) isolated from rat MAB. Ethanol increased ROS generation, and this response was not affected by AG1296, a PDGF-R inhibitor, or losartan. Finally, ethanol did not alter MAPK or PDGF-R phosphorylation in cultured VSMC. Our study provides novel evidence that acute ethanol intake induces ROS generation, PDGF-R phosphorylation, and MAPK activation through AT(1)-independent mechanisms in resistance arteries in vivo. MAPK and PDGF-R play a role in vascular signaling and cardiovascular diseases and may contribute to the vascular pathobiology of ethanol.
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72
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Silveira ALBD, de Souza Miranda MF, Mecawi AS, Melo RL, Marassi MP, Matos da Silva AC, Antunes-Rodrigues J, Olivares EL. Sexual dimorphism in autonomic changes and in the renin-angiotensin system in the hearts of mice subjected to thyroid hormone-induced cardiac hypertrophy. Exp Physiol 2014; 99:868-80. [PMID: 24659612 DOI: 10.1113/expphysiol.2013.076976] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Based on the relevance of the renin-angiotensin system and the ongoing controversy regarding the role of the sympathetic nervous system in thyroid hormone-induced cardiac hypertrophy, the aim of the present study was to establish whether the putative difference in the degree of cardiac hypertrophy exhibited by males and females might be related to differences in the sympathetic-vagal balance and/or in the cardiac renin-angiotensin system in mice of different genders. Male and female mice (n = 117) were given 0.1 mg kg(-1) of triiodothyronine or normal saline each day for 10 days consecutively. At the end of that period, study of the heart rate variability, spectral analysis and histopathological examination were performed to assess the sympathetic-vagal balance and the diameter of cardiomyocytes. The cardiac levels of angiotensin I and II were also measured. Treatment with triiodothyronine induced a greater degree of cardiac hypertrophy in male (~73%) than in female mice (~42%). This difference was attributed to greater modulation of the sympathetic nervous system and higher levels of angiotensin I and II in male than in female mice. Our data indicate that thyroid hormone-induced cardiac hypertrophy was more intense in male mice due to the synergic effect of the sympathetic nervous system and the cardiac renin-angiotensin system.
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73
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Abstract
Studies of body volume expansion have indicated that lesions of the anteroventral third ventricle and median eminence block the release of atrial natriuretic peptide (ANP) into the circulation. Detailed analysis of the lesions showed that activation of oxytocin (OT)-ergic neurons is responsible for ANP release, and it has become clear that activation of neuronal circuitry elicits OT secretion into the circulation, activating atrial OT receptors and ANP release from the heart. Subsequently, we have uncovered the entire functional OT system in the rat and the human heart. An abundance of OT has been observed in the early development of the fetal heart, and the capacity of OT to generate cardiomyocytes (CMs) has been demonstrated in various types of stem cells. OT treatment of mesenchymal stem cells stimulates paracrine factors beneficial for cardioprotection. Cardiovascular actions of OT include: i) lowering blood pressure, ii) negative inotropic and chronotropic effects, iii) parasympathetic neuromodulation, iv) vasodilatation, v) anti-inflammatory activity, vi) antioxidant activity, and vii) metabolic effects. OT actions are mediated by nitric oxide and ANP. The beneficial actions of OT may include the increase in glucose uptake by CMs and stem cells, reduction in CM hypertrophy, oxidative stress, and mitochondrial protection of several cell types. In experimentally induced myocardial infarction in rats, continuous in vivo OT delivery improves cardiac healing and cardiac work, reduces inflammation, and stimulates angiogenesis. Because OT plays anti-inflammatory and cardioprotective roles and improves vascular and metabolic functions, it demonstrates potential for therapeutic use in various pathologic conditions.
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74
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de Carvalho Borges B, Rorato R, Uchoa ET, Marangon P, da Silva GSF, de Paula FJ, Branco LGS, Antunes-Rodrigues J, Elias LLK. High-fat diet induces site-specific unresponsiveness to LPS-stimulated STAT3 activation in the hypothalamus. Am J Physiol Regul Integr Comp Physiol 2014; 306:R34-44. [DOI: 10.1152/ajpregu.00147.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hypophagia induced by inflammation is associated with Janus kinase (JAK)-2/signal transducer and activator of transcription (STAT) 3 signaling pathway, and leptin-mediated hypophagia is also mediated by JAK2-STAT3 pathway. We have previously reported that lipopolysaccharide (LPS) did not reduce food intake in leptin-resistant high-fat diet (HFD) rats but maintained body weight loss. We investigated whether changes in p-STAT3 expression in the hypothalamus and brain stem could account for the desensitization of hypophagia in HFD animals after a low LPS dose (100 μg/kg). Wistar rats fed standard diet (3.95 kcal/g) or HFD (6.3 kcal/g) for 8 wk were assigned into control diet-saline, control diet-LPS, HFD-saline, and HFD-LPS groups. LPS reduced feeding in the control diet but not HFD. This group showed no p-STAT3 expression in the paraventricular nucleus (PVN) and ventromedial hypothalamic nucleus (VMH), but sustained, though lower than control, p-STAT3 in the nucleus of the solitary tract (NTS) and raphe pallidus (RPa). LPS decreased body weight in HFD rats and increased Fos expression in the NTS. LPS increased body temperature, oxygen consumption, and energy expenditure in both control diet and HFD rats, and this response was more pronounced in HFD-LPS group. Brown adipose tissue (BAT) thermogenesis and increased energy expenditure seem to contribute to body weight loss in HFD-LPS. This response might be related with increased brain stem activation. In conclusion, LPS activates STAT3-mediated pathway in the hypothalamus and brain stem, leading to hypophagia, however, LPS effects on food intake, but not body weight loss, are abolished by leptin resistance induced by HFD. The preserved STAT3 phosphorylation in the brain stem suggests that unresponsiveness to LPS on STAT3 activation under HFD might be selective to the hypothalamus.
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75
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Almeida-Pereira G, Rorato R, Reis LC, Elias LLK, Antunes-Rodrigues J. The role of estradiol in adrenal insufficiency and its interaction with corticosterone on hydromineral balance. Horm Behav 2013; 64:847-55. [PMID: 24396886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Estradiol (E2) plays an important role in controlling the homeostasis of body fluids. Several studies have reported the involvement of the hypothalamic pituitary adrenal axis (HPA) in the homeostatic control of hydromineral balance and the influence of estrogens on the modulation of this system. Nevertheless, until now, the physiological relevance of HPA axis activity on the hydromineral balance in females has not yet been fully elucidated. Therefore, the objective of the present study was to evaluate the effects of E2 (20 μg/animal) pretreatment on neuroendocrine and hydroelectrolyte changes induced by adrenalectomy (ADX) with or without glucocorticoid hormone replacement (corticosterone, CORT; 10 mg/kg) in ovariectomized rats (OVX). The results show that sodium appetite, natriuresis and the elevated plasma angiotensin II (ANG II) concentration induced by ADX were attenuated by E2 pretreatment. Additionally, a reduction of AT1 mRNA expression in the subfornical organ (SFO) and an increase in plasma atrial natriuretic peptide (ANP) concentrations by E2 pretreatment were observed. E2 pretreatment reversed the reduction in water intake induced by ADX in ADX CORT-replaced rats. Moreover, E2 pretreatment attenuated corticotropin releasing factor (CRF) mRNA expression in the paraventricular nucleus (PVN) induced by ADX. In contrast, E2 pretreatment increased CRF mRNA expression in the PVN in ADX CORT-replaced rats. Taken together, these results suggest that E2 has an important role in the modulation of behavioral and neuroendocrine responses involved in the maintenance of body fluid homeostasis in ADX rats with or without glucocorticoid replacement therapy.
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