ORCID Profile
0000-0002-7511-5035
Current Organisation
Universidade Federal de Goiás
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Publisher: Public Library of Science (PLoS)
Date: 03-10-2014
Publisher: Cambridge University Press (CUP)
Date: 27-10-2014
DOI: 10.1017/S0007114514002918
Abstract: Epigenetic studies suggest that diseases that develop in adulthood are related to certain conditions to which the in idual is exposed during the initial stages of life. Experimental evidence has demonstrated that offspring born to mothers maintained on high-Na diets during pregnancy have higher mean arterial pressure (MAP) in adulthood. Although these studies have demonstrated the importance of prenatal phases to hypertension development, no evidence regarding the role of high Na intake during postnatal phases in the development of this pathology has been reported. Therefore, in the present study, the effects of Na overload during childhood on induced water and Na intakes and on cardiovascular parameters in adulthood were evaluated. Experiments were carried out in two groups of 21-d-old rats: experimental group, maintained on hypertonic saline (0·3 m- NaCl) solution and food for 60 d, and control group, maintained on tap water and food. Later, both groups were given water and food for 15 d (recovery period). After the recovery period, chronic cannulation of the right femoral artery was performed in unanaesthetised rats to record baseline MAP and heart rate (HR). The experimental group was found to have increased basal MAP (98·6 ( sem 2·6) v . 118·3 ( sem 2·7) mmHg, P 0·05) and HR (365·4 ( sem 12·2) v . 398·2 ( sem 7·5) beats per min, P 0·05). There was a decrease in the baroreflex index in the experimental group when compared with that in the control group. A water and Na intake test was performed using furosemide. Na depletion was found to induce an increase in Na intake in both the control and experimental groups (12·1 ( sem 0·6) ml and 7·8 ( sem 1·1), respectively, P 0·05) however, this increase was of lower magnitude in the experimental group. These results demonstrate that postnatal Na overload alters behavioural and cardiovascular regulation in adulthood.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.NEULET.2013.11.001
Abstract: Studies have demonstrated that median preoptic nucleus (MnPO) neurons play a role in organizing the cardiovascular responses induced by changes in the circulating blood volume. The present study examined whether the MnPO controls cardiovascular function. Male Wistar normotensive (NT) rats and spontaneously hypertensive rats (SHRs 250-300 g) were anesthetized with urethane (1.2 g kg(-1), i.v.) and instrumented for recordings of mean arterial blood pressure (MAP) and renal blood flow (RBF). The renal vascular conductance (RVC) was calculated as the RBF:MAP ratio and was expressed as a percentage of the baseline value. In the NT rats (n=6), MnPO inhibition produced a MAP reduction (-8.1±1.1 mmHg, p<0.05). In the SHRs (n=6), the MAP response to MnPO inhibition was significantly greater (-22.3±4 mmHg, p<0.05) than in the NT rats. Furthermore, the increase in the RVC was higher in the SHRs (10.9±3.3%, p<0.05). Histological analyses confirmed that the injection sites were confined to the MnPO. We conclude that the MnPO is involved in the tonic regulation of blood pressure in NT rats. Moreover, the greater cardiovascular response to MnPO inhibition observed in the SHRs strongly suggests that the MnPO may contribute to the pathophysiology of essential hypertension.
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.BRAINRESBULL.2008.04.001
Abstract: Several findings suggest that catecholaminergic neurons in the caudal ventrolateral medulla (CVLM) contribute to body fluid homeostasis and cardiovascular regulation. From the CVLM other areas in central nervous system involved in cardiovascular regulation and hydroelectrolyte balance can be activated. Therefore, the aim of the present study was to investigate the effects of lesions of these neurons on 0.3M NaCl and water intake induced by subcutaneous injection of furosemide (FURO)+captopril (CAP) or 36 h of water deprivation artial hydration with only water (WD/PR). Male Wistar rats (320-360 g) were submitted to medullary catecholaminergic neuron lesions by microinjection of anti-dopamine-beta-hydroxylase-saporin (anti-DbetaH-saporin 6.3 ng in 60 nl) into the CVLM (SAP-rats). Sham rats received microinjections of free saporin (1.3 ng in 60 nl) in the same region. In SAP-rats, the 0.3M NaCl intake was increased after FURO+CAP (6.8+/-1.0 ml/2h, vs. sham: 3.7+/-0.7 ml/2h) as well as after WD/PR (11.1+/-1.3 ml/2h vs. sham: 6.1+/-1.8 ml/2h). Conversely, in SAP-rats, the water intake induced by FURO+CAP (14.8+/-1.3 ml/2h, vs. sham: 14.1+/-1.6 ml/2h) or by WD/PR (3.6+/-0.9 ml/2h, vs. sham: 3.2+/-1.1 ml/2h) was not different from sham rats. Immunohistochemical analysis indicates that microinjections of anti-DbetaH-saporin produced extensive destruction within the A1 cell groups in the CVLM. These results suggest an inhibitory role for medullary catecholaminergic neurons on sodium appetite.
Publisher: Hindawi Limited
Date: 2014
DOI: 10.1155/2014/496121
Abstract: Changes in plasma osmolarity, through central and peripheral osmoreceptors, activate the median preoptic nucleus (MnPO) that modulates autonomic and neuroendocrine adjustments. The present study sought to determine the participation of MnPO in the cardiovascular recovery induced by hypertonic saline infusion (HSI) in rats submitted to hemorrhagic shock. The recordings of mean arterial pressure (MAP) and renal vascular conductance (RVC) were carried out on male Wistar rats (250–300 g). Hemorrhagic shock was induced by blood withdrawal over 20 min until the MAP values of approximately 60 mmHg were attained. The nanoinjection (100 nL) of GABA A agonist (Muscimol 4 mM experimental group (EXP)) or isotonic saline (NaCl 150 mM control (CONT)) into MnPO was performed 2 min prior to intravenous overload of sodium through HSI (3 M NaCl, 1.8 mL/kg, b.wt.). Hemorrhagic shock reduced the MAP in control ( 62 ± 1.1 mmHg) and EXP ( 61 ± 0.4 mmHg) equipotently. The inhibition of MnPO impaired MAP (CONT: 104 ± 4.2 versus EXP: 60 ± 6.2 mmHg) and RVC (CONT: 6.4 ± 11.4 versus EXP: -53.5 ± 10.0 ) recovery 10 min after HSI. The overall results in this study demonstrated, for the first time, that the MnPO plays an essential role in the HSI induced resuscitation during hypovolemic hemorrhagic shock.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.BRAINRESBULL.2018.06.011
Abstract: The crucial role of the median preoptic nucleus (MnPO) in the maintenance of hydroelectrolytic balance and autonomic regulation have been highlighted. Recently, the participation of the MnPO in the control of sympathetic nerve activity was demonstrated in essential hypertension model. However, peculiarities on the neurochemical changes underlying the differential role of MnPO during hypertension remain to be clarified. Therefore, this study aimed to investigate the main excitatory pathways that modulate MnPO neurons in hypertensive rats. Spontaneously hypertensive rats (SHR) and rats submitted previously to the Goldblatt protocol (two kidneys one clip 2K1C) were used. Rats of both groups (250 to 350 g, n = 6) were anesthetized with urethane (1.2 g/kg,i.v.) and instrumented to record mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA). Nanoinjection (100 nl) of saline (NaCl, 150 mM), losartan (AT1 receptor antagonist 10 mM) and kynurenic acid (glutamate receptor antagonist 50 mM) into the MnPO were performed. In 2K1C rats, glutamatergic blockade promoted decreases in MAP and RSNA (-19.1 ± 0.9 mmHg, -21.6 ± 2.8%, p < 0.05) when compared to saline (-0.4 ± 0.6 mmHg, 0.2 ± 0.7%, p < 0.05). Angiotensinergic inhibition also reduced these parameters (-11.5 ± 1.2 mmHg, -10.5 ± 1.0%, p < 0.05) in 2K1C. In SHR, Kynurenic acid nanoinjections produced hypotension and sympathoinhibition (-21.0 ± 2.5 mmHg, -24.7 ± 2.4%, p < 0.05), as well losartan nanoinjections (-9.7 ± 1.2 mmHg p < 0.05) and RSNA (-12.0 ± 2.4%, p < 0.05). These findings support the conclusion that a tonic excitatory neurotransmission exerted by angiotensin II, and mostly by glutamate in the MnPO could participate in the modulation of blood pressure and RSNA independent on whether hypertension is primarily neurogenic or is secondary to stenosis in renal artery.
Location: Brazil
No related grants have been discovered for Andre Henrique Freiria-Oliveira.