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Lauar MR, Pestana-Oliveira N, Collister JP, Vulchanova L, Evans LC, Osborn JW. The organum vasculosum of the lamina terminalis contributes to neurohumoral mechanisms of renal vascular hypertension. Am J Physiol Regul Integr Comp Physiol 2025; 328:R161-R171. [PMID: 39705721 DOI: 10.1152/ajpregu.00203.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2024] [Revised: 12/12/2024] [Accepted: 12/16/2024] [Indexed: 12/22/2024]
Abstract
The organum vasculosum of the lamina terminalis (OVLT) is a forebrain circumventricular organ that modulates central autonomic control of arterial pressure and body fluid homeostasis. It has been implicated in the pathogenesis of rat models of hypertension that are driven by increased salt intake since OVLT lesion (OVLTx) attenuates both the DOCA-salt and angiotensin II-salt models. However, its contribution to the development of hypertension that is not salt-dependent, such as the 2 kidney, 1 clip (2K1C) renovascular model, is not clear. We recently reported that afferent renal denervation (ARDN) attenuates the pathogenesis of 2K1C hypertension in the rat and this was associated with a reduction of neurogenic pressor activity, water intake, vasopressin release, and renal inflammation, suggesting that afferent renal nerves, similar to OVLT, modulates central autonomic pathways that control arterial pressure and body fluid homeostasis. This idea led to the present study, which was designed to measure the effect of OVLTx on arterial pressure and body fluid homeostasis in 2K1C-HTN rats. Male Sprague-Dawley rats were randomly selected to receive OVLTx or sham operation and were instrumented 1 wk later with telemeters to continuously measure mean arterial pressure (MAP). The following week, rats received a silver clip around the left renal artery to generate 2K1C hypertension or sham-clip surgery. MAP was continuously measured for 6 wk, and once a week, rats were housed in metabolic cages for 24 h to evaluate water intake and urinary volume. Urine was analyzed for inflammatory cytokines and copeptin, a surrogate marker of vasopressin. Neurogenic pressor activity (NPA) was assessed on the last day of the protocol by measuring the peak MAP response to ganglionic blockade. Upon completion of the study, rats were euthanized and kidneys were removed for the measurement of inflammatory cytokine content. Hypertension in 2K1C rats was associated with increased NPA, water intake, vasopressin release, and renal inflammation. All of these responses were markedly attenuated or abolished in OVLTx 2K1C rats. These findings suggest that the OVLT, similar to afferent renal nerves, plays a key role in the development of hypertension, polydipsia, vasopressin release, and renal inflammation in 2K1C-HTN rats.NEW & NOTEWORTHY Renovascular hypertension (RVHT), accounting for 1%-5% of high blood pressure cases, is the most common secondary hypertension resistant to treatment. In two-kidney one-clip (2K1C) hypertensive rats, renal artery stenosis triggers sympathetic nervous system activation, increased vasopressin, water intake, and inflammation. OVLT lesions prevented these responses, similar to afferent renal denervation. This study suggests that OVLT plays a key role in 2K1C hypertension pathogenesis and interacts with afferent renal nerves. Future studies will explore the underlying mechanisms.
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Affiliation(s)
- Mariana R Lauar
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, Minnesota, United States
| | - Nayara Pestana-Oliveira
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, Minnesota, United States
| | - John P Collister
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, United States
| | - Lucy Vulchanova
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States
| | - Louise C Evans
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, Minnesota, United States
| | - John W Osborn
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, Minnesota, United States
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Lauar MR, Colombari DSA, De Paula PM, Colombari E, Andrade CAF, De Luca LA, Menani JV. Chronic administration of catalase inhibitor attenuates hypertension in renovascular hypertensive rats. Life Sci 2023; 319:121538. [PMID: 36868399 DOI: 10.1016/j.lfs.2023.121538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/18/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023]
Abstract
AIMS Reactive oxygen species like hydrogen peroxide (H2O2) are produced endogenously and may participate in intra- and extracellular signaling, including modulation of angiotensin II responses. In the present study, we investigated the effects of chronic subcutaneous (sc) administration of the catalase inhibitor 3-amino-1,2,4-triazole (ATZ) on arterial pressure, autonomic modulation of arterial pressure, hypothalamic expression of AT1 receptors and neuroinflammatory markers and fluid balance in 2-kidney, 1clip (2K1C) renovascular hypertensive rats. MATERIALS AND METHODS Male Holtzman rats with a clip occluding partially the left renal artery and chronic sc injections of ATZ were used. KEY FINDINGS Subcutaneous injections of ATZ (600 mg/kg of body weight/day) for 9 days in 2K1C rats reduced arterial pressure (137 ± 8, vs. saline: 182 ± 8 mmHg). ATZ also reduced the sympathetic modulation and enhanced the parasympathetic modulation of pulse interval, reducing the sympatho-vagal balance. Additionally, ATZ reduced mRNA expression for interleukins 6 and IL-1β, tumor necrosis factor-α, AT1 receptor (0.77 ± 0.06, vs. saline: 1.47 ± 0.26 fold change), NOX 2 (0.85 ± 0.13, vs. saline: 1.75 ± 0.15 fold change) and the marker of microglial activation, CD 11 (0.47 ± 0.07, vs. saline, 1.34 ± 0.15 fold change) in the hypothalamus of 2K1C rats. Daily water and food intake and renal excretion were only slightly modified by ATZ. SIGNIFICANCE The results suggest that the increase of endogenous H2O2 availability with chronic treatment with ATZ had an anti-hypertensive effect in 2K1C hypertensive rats. This effect depends on decreased activity of sympathetic pressor mechanisms and mRNA expression of AT1 receptors and neuroinflammatory markers possibly due to reduced angiotensin II action.
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Affiliation(s)
- Mariana R Lauar
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - Patrícia M De Paula
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - Carina A F Andrade
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - Laurival A De Luca
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - José V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
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Pereira ED, Oliveira LM, Coletto-Nunes G, Souza PPC, Menani JV, De Luca LA, Andrade CAF. Central angiotensinergic mechanisms in female spontaneously hypertensive rats treated with estradiol. Appetite 2022; 174:106012. [PMID: 35367482 DOI: 10.1016/j.appet.2022.106012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 11/17/2022]
Abstract
Estrogens reduce 0.3 M NaCl intake and palatability in a widely used model of essential hypertension, the spontaneously hypertensive rats (SHRs). Here we investigated whether the inhibitory effects of β-estradiol (E2, 10 μg/kg b.w. subcutaneously for 8 days) on water deprived partially-rehydrated (WD-PR) ovariectomized (OVX) adult female SHRs (fSHRs, n = 4-10/group) are related to interferences on brain angiotensin II AT1 receptors (AT1r). After WD-PR, E2 reduced 0.3 M NaCl intake (1.3 ± 0.6, vs. vehicle: 3.5 ± 1.2 ml/30 min), the number of hedonic responses to intraoral NaCl infusion (57 ± 11, vs. vehicle: 176 ± 32/min), and the relative angiotensin AT1r (Agtr1a) mRNA expression in the hypothalamus. Losartan (AT1r antagonist, 100 μg) intracerebroventricularly in OVX fSHRs treated with vehicle subcutaneously abolished 0.3 M NaCl intake (0.1 ± 0.1 ml/30 min) and only transiently reduced hedonic responses to intraoral NaCl. Losartan combined with E2 decreased the number of hedonic and increased the number of aversive responses to intraoral NaCl and abolished 0.3 M NaCl intake. E2 also reduced the pressor and dipsogenic responses to intracerebroventricular angiotensin II. The results suggest that AT1r activation increases palatability and induces NaCl intake in WD-PR fSHRs. E2 reduced hypothalamic Agtr1a mRNA expression, which may account for the effects of E2 on NaCl intake and palatability and intracerebroventricular angiotensin II-induced pressor and dipsogenic responses in OVX fSHRs. Future studies considering natural fluctuations in estrogen secretion might help to determine the degree of such interference in brain neuronal activity.
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Affiliation(s)
- E D Pereira
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil
| | - L M Oliveira
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil
| | - G Coletto-Nunes
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil
| | - P P C Souza
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil
| | - L A De Luca
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil
| | - C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, UNESP, Araraquara, SP, 14801-903, Brazil.
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Frame AA, Nist KM, Kim K, Kuwabara JT, Wainford RD. Natriuresis During an Acute Intravenous Sodium Chloride Infusion in Conscious Sprague Dawley Rats Is Mediated by a Blood Pressure-Independent α1-Adrenoceptor-Mediated Mechanism. Front Physiol 2022; 12:784957. [PMID: 35111076 PMCID: PMC8802910 DOI: 10.3389/fphys.2021.784957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
The mechanisms that sense alterations in total body sodium content to facilitate sodium homeostasis in response to an acute sodium challenge that does not increase blood pressure have not been fully elucidated. We hypothesized that the renal sympathetic nerves are critical to mediate natriuresis via α1- or β-adrenoceptors signal transduction pathways to maintain sodium balance in the face of acute increases in total body sodium content that do not activate the pressure-natriuresis mechanism. To address this hypothesis, we used acute bilateral renal denervation (RDNX), an anteroventral third ventricle (AV3V) lesion and α1- or β-antagonism during an acute 1M NaCl sodium challenge in conscious male Sprague Dawley rats. An acute 1M NaCl infusion did not alter blood pressure and evoked profound natriuresis and sympathoinhibition. Acute bilateral RDNX attenuated the natriuretic and sympathoinhibitory responses evoked by a 1M NaCl infusion [peak natriuresis (μeq/min) sham 14.5 ± 1.3 vs. acute RDNX: 9.2 ± 1.4, p < 0.05; plasma NE (nmol/L) sham control: 44 ± 4 vs. sham 1M NaCl infusion 11 ± 2, p < 0.05; acute RDNX control: 42 ± 6 vs. acute RDNX 1M NaCl infusion 25 ± 3, p < 0.05]. In contrast, an AV3V lesion did not impact the cardiovascular, renal excretory or sympathoinhibitory responses to an acute 1M NaCl infusion. Acute i.v. α1-adrenoceptor antagonism with terazosin evoked a significant drop in baseline blood pressure and significantly attenuated the natriuretic response to a 1M NaCl load [peak natriuresis (μeq/min) saline 17.2 ± 1.4 vs. i.v. terazosin 7.8 ± 2.5, p < 0.05]. In contrast, acute β-adrenoceptor antagonism with i.v. propranolol infusion did not impact the cardiovascular or renal excretory responses to an acute 1M NaCl infusion. Critically, the natriuretic response to an acute 1M NaCl infusion was significantly blunted in rats receiving a s.c. infusion of the α1-adrenoceptor antagonist terazosin at a dose that did not lower baseline blood pressure [peak natriuresis (μeq/min) sc saline: 18 ± 1 vs. sc terazosin 7 ± 2, p < 0.05]. Additionally, a s.c. infusion of the α1-adrenoceptor antagonist terazosin further attenuated the natriuretic response to a 1M NaCl infusion in acutely RDNX animals. Collectively these data indicate a specific role of a blood pressure-independent renal sympathetic nerve-dependent α1-adrenoceptor-mediated pathway in the natriuretic and sympathoinhibitory responses evoked by acute increases in total body sodium.
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Affiliation(s)
- Alissa A. Frame
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Kayla M. Nist
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Kiyoung Kim
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Jill T. Kuwabara
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Richard D. Wainford
- Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: Richard D. Wainford,
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Moreira JD, Nist KM, Carmichael CY, Kuwabara JT, Wainford RD. Sensory Afferent Renal Nerve Activated Gαi 2 Subunit Proteins Mediate the Natriuretic, Sympathoinhibitory and Normotensive Responses to Peripheral Sodium Challenges. Front Physiol 2021; 12:771167. [PMID: 34916958 PMCID: PMC8669768 DOI: 10.3389/fphys.2021.771167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/09/2021] [Indexed: 11/15/2022] Open
Abstract
We have previously reported that brain Gαi2 subunit proteins are required to maintain sodium homeostasis and are endogenously upregulated in the hypothalamic paraventricular nucleus (PVN) in response to increased dietary salt intake to maintain a salt resistant phenotype in rats. However, the origin of the signal that drives the endogenous activation and up-regulation of PVN Gαi2 subunit protein signal transduction pathways is unknown. By central oligodeoxynucleotide (ODN) administration we show that the pressor responses to central acute administration and central infusion of sodium chloride occur independently of brain Gαi2 protein pathways. In response to an acute volume expansion, we demonstrate, via the use of selective afferent renal denervation (ADNX) and anteroventral third ventricle (AV3V) lesions, that the sensory afferent renal nerves, but not the sodium sensitive AV3V region, are mechanistically involved in Gαi2 protein mediated natriuresis to an acute volume expansion [peak natriuresis (μeq/min) sham AV3V: 43 ± 4 vs. AV3V 45 ± 4 vs. AV3V + Gαi2 ODN 25 ± 4, p < 0.05; sham ADNX: 43 ± 4 vs. ADNX 23 ± 6, AV3V + Gαi2 ODN 25 ± 3, p < 0.05]. Furthermore, in response to chronically elevated dietary sodium intake, endogenous up-regulation of PVN specific Gαi2 proteins does not involve the AV3V region and is mediated by the sensory afferent renal nerves to counter the development of the salt sensitivity of blood pressure (MAP [mmHg] 4% NaCl; Sham ADNX 124 ± 4 vs. ADNX 145 ± 4, p < 0.05; Sham AV3V 125 ± 4 vs. AV3V 121 ± 5). Additionally, the development of the salt sensitivity of blood pressure following central ODN-mediated Gαi2 protein down-regulation occurs independently of the actions of the brain angiotensin II type 1 receptor. Collectively, our data suggest that in response to alterations in whole body sodium the peripheral sensory afferent renal nerves, but not the central AV3V sodium sensitive region, evoke the up-regulation and activation of PVN Gαi2 protein gated pathways to maintain a salt resistant phenotype. As such, both the sensory afferent renal nerves and PVN Gαi2 protein gated pathways, represent potential targets for the treatment of the salt sensitivity of blood pressure.
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Affiliation(s)
- Jesse D. Moreira
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Medicine, School of Medicine, Boston University, Boston, MA, United States
| | - Kayla M. Nist
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, School of Medicine, Boston University, Boston, MA, United States
| | - Casey Y. Carmichael
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
| | - Jill T. Kuwabara
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
| | - Richard D. Wainford
- Whitaker Cardiovascular Institute, School of Medicine, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Boston University, Boston, MA, United States
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Marques SM, Naves LM, Silva TDME, Cavalcante KVN, Alves JM, Ferreira-Neto ML, de Castro CH, Freiria-Oliveira AH, Fajemiroye JO, Gomes RM, Colombari E, Xavier CH, Pedrino GR. Medullary Noradrenergic Neurons Mediate Hemodynamic Responses to Osmotic and Volume Challenges. Front Physiol 2021; 12:649535. [PMID: 33967822 PMCID: PMC8103169 DOI: 10.3389/fphys.2021.649535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/04/2021] [Indexed: 11/16/2022] Open
Abstract
Despite being involved in homeostatic control and hydro-electrolyte balance, the contribution of medullary (A1 and A2) noradrenergic neurons to the hypertonic saline infusion (HSI)-induced cardiovascular response after hypotensive hemorrhage (HH) remains to be clarified. Hence, the present study sought to determine the role of noradrenergic neurons in HSI-induced hemodynamic recovery in male Wistar rats (290–320 g) with HH. Medullary catecholaminergic neurons were lesioned by nanoinjection of antidopamine-β-hydroxylase–saporin (0.105 ng·nl−1) into A1, A2, or both (LES A1; LES A2; or LES A1+A2, respectively). Sham rats received nanoinjections of free saporin in the same regions (SHAM A1; SHAM A2; or SHAM A1+A2, respectively). After 15 days, rats were anesthetized and instrumented for cardiovascular recordings. Following 10 min of stabilization, HH was performed by withdrawing arterial blood until mean arterial pressure (MAP) reaches 60 mmHg. Subsequently, HSI was performed (NaCl 3 M; 1.8 ml·kg−1, i.v.). The HH procedure caused hypotension and bradycardia and reduced renal, aortic, and hind limb blood flows (RBF, ABF, and HBF). The HSI restored MAP, heart rate (HR), and RBF to baseline values in the SHAM, LES A1, and LES A2 groups. However, concomitant A1 and A2 lesions impaired this recovery, as demonstrated by the abolishment of MAP, RBF, and ABF responses. Although lesioning of only a group of neurons (A1 or A2) was unable to prevent HSI-induced recovery of cardiovascular parameters after hemorrhage, lesions of both A1 and A2 made this response unfeasible. These findings show that together the A1 and A2 neurons are essential to HSI-induced cardiovascular recovery in hypovolemia. By implication, simultaneous A1 and A2 dysfunctions could impair the efficacy of HSI-induced recovery during hemorrhage.
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Affiliation(s)
- Stefanne Madalena Marques
- Department of Physiology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil
| | - Lara Marques Naves
- Department of Physiology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil
| | - Talita de Melo E Silva
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | | | - Juliana Milan Alves
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Marcos Luiz Ferreira-Neto
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Carlos Henrique de Castro
- Department of Physiology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil
| | | | | | - Rodrigo Mello Gomes
- Department of Physiology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, Brazil
| | - Carlos Henrique Xavier
- Department of Physiology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil
| | - Gustavo Rodrigues Pedrino
- Department of Physiology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil
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Andrade-Franzé GMF, Pereira ED, Yosten GLC, Samson WK, Menani JV, De Luca LA, Andrade CAF. Blockade of ERK1/2 activation with U0126 or PEP7 reduces sodium appetite and angiotensin II-induced pressor responses in spontaneously hypertensive rats. Peptides 2021; 136:170439. [PMID: 33166587 DOI: 10.1016/j.peptides.2020.170439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 01/06/2023]
Abstract
Spontaneously hypertensive rats (SHRs) have increased daily or induced sodium intake compared to normotensive rats. In normotensive rats, angiotensin II (ANG II)-induced sodium intake is blocked by the inactivation of p42/44 mitogen-activated protein kinase, also known as extracellular signal-regulated protein kinase1/2 (ERK1/2). Here we investigated if inhibition of ERK1/2 pathway centrally would change sodium appetite and intracerebroventricular (icv) ANG II-induced pressor response in SHRs. SHRs (280-330 g, n = 07-14/group) with stainless steel cannulas implanted in the lateral ventricle (LV) were used. Water and 0.3 M NaCl intake was induced by the treatment with the diuretic furosemide + captopril (angiotensin converting enzyme blocker) subcutaneously or 24 h of water deprivation (WD) followed by 2 h of partial rehydration with only water (PR). The blockade of ERK1/2 activation with icv injections of U0126 (MEK1/2 inhibitor, 2 mM; 2 μl) reduced 0.3 M NaCl intake induced by furosemide + captopril (5.0 ± 1.0, vs. vehicle: 7.3 ± 0.7 mL/120 min) or WD-PR (4.6 ± 1.3, vs. vehicle: 10.3 ± 1.4 mL/120 min). PEP7 (selective inhibitor of AT1 receptor-mediated ERK1/2 activation, 2 nmol/2 μL) icv also reduced WD-PR-induced 0.3 M NaCl (2.8 ± 0.7, vs. vehicle: 6.8 ± 1.4 mL/120 min). WD-PR-induced water intake was also reduced by U0126 or PEP7. In addition, U0126 or PEP7 icv reduced the pressor response to icv ANG II. Therefore, the present results suggest that central AT1 receptor-mediated ERK1/2 activation is part of the mechanisms involved in sodium appetite and ANG II-induced pressor response in SHRs.
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Affiliation(s)
- G M F Andrade-Franzé
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - E D Pereira
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - G L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - W K Samson
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - L A De Luca
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil.
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8
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Gasparini S, Howland JM, Thatcher AJ, Geerling JC. Central afferents to the nucleus of the solitary tract in rats and mice. J Comp Neurol 2020; 528:2708-2728. [PMID: 32307700 DOI: 10.1002/cne.24927] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022]
Abstract
The nucleus of the solitary tract (NTS) regulates life-sustaining functions ranging from appetite and digestion to heart rate and breathing. It is also the brain's primary sensory nucleus for visceral sensations relevant to symptoms in medical and psychiatric disorders. To better understand which neurons may exert top-down control over the NTS, here we provide a brain-wide map of all neurons that project axons directly to the caudal, viscerosensory NTS, focusing on a medial subregion with aldosterone-sensitive HSD2 neurons. Injecting an axonal tracer (cholera toxin b) into the NTS produces a similar pattern of retrograde labeling in rats and mice. The paraventricular hypothalamic nucleus (PVH), lateral hypothalamic area, and central nucleus of the amygdala (CeA) contain the densest concentrations of NTS-projecting neurons. PVH afferents are glutamatergic (express Slc17a6/Vglut2) and are distinct from neuroendocrine PVH neurons. CeA afferents are GABAergic (express Slc32a1/Vgat) and are distributed largely in the medial CeA subdivision. Other retrogradely labeled neurons are located in a variety of brain regions, including the cerebral cortex (insular and infralimbic areas), bed nucleus of the stria terminalis, periaqueductal gray, Barrington's nucleus, Kölliker-Fuse nucleus, hindbrain reticular formation, and rostral NTS. Similar patterns of retrograde labeling result from tracer injections into different NTS subdivisions, with dual retrograde tracing revealing that many afferent neurons project axon collaterals to both the lateral and medial NTS subdivisions. This information provides a roadmap for studying descending axonal projections that may influence visceromotor systems and visceral "mind-body" symptoms.
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Affiliation(s)
- Silvia Gasparini
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
| | - Jacob M Howland
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
| | - Andrew J Thatcher
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
| | - Joel C Geerling
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa, Iowa city, Iowa, USA
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9
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Anti-hypertensive effect of hydrogen peroxide acting centrally. Hypertens Res 2020; 43:1192-1203. [PMID: 32461634 DOI: 10.1038/s41440-020-0474-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 04/20/2020] [Accepted: 04/29/2020] [Indexed: 11/09/2022]
Abstract
Intracerebroventricular (icv) injection of hydrogen peroxide (H2O2) or the increase of endogenous H2O2 centrally produced by catalase inhibition with 3-amino-1,2,4-triazole (ATZ) injected icv reduces the pressor responses to central angiotensin II (ANG II) in normotensive rats. In the present study, we investigated the changes in the arterial pressure and in the pressor responses to ANG II icv in spontaneously hypertensive rats (SHRs) and 2-kidney, 1-clip (2K1C) hypertensive rats treated with H2O2 injected icv or ATZ injected icv or intravenously (iv). Adult male SHRs or Holtzman rats (n = 5-10/group) with stainless steel cannulas implanted in the lateral ventricle were used. In freely moving rats, H2O2 (5 μmol/1 μl) or ATZ (5 nmol/1 μl) icv reduced the pressor responses to ANG II (50 ng/1 µl) icv in SHRs (11 ± 3 and 17 ± 4 mmHg, respectively, vs. 35 ± 6 mmHg) and 2K1C hypertensive rats (3 ± 1 and 16 ± 3 mmHg, respectively, vs. 26 ± 2 mmHg). ATZ (3.6 mmol/kg of body weight) iv alone or combined with H2O2 icv also reduced icv ANG II-induced pressor response in SHRs and 2K1C hypertensive rats. Baseline arterial pressure was also reduced (-10 to -15 mmHg) in 2K1C hypertensive rats treated with H2O2 icv and ATZ iv alone or combined and in SHRs treated with H2O2 icv alone or combined with ATZ iv. The results suggest that exogenous or endogenous H2O2 acting centrally produces anti-hypertensive effects impairing central pressor mechanisms activated by ANG II in SHRs or 2K1C hypertensive rats.
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Naves LM, Marques SM, Mourão AA, Fajemiroye JO, Xavier CH, de Castro CH, Rebelo ACS, Rosa DA, Gomes RM, Colombari E, Pedrino GR. Involvement of median preoptic nucleus and medullary noradrenergic neurons in cardiovascular and sympathetic responses of hemorrhagic rats. Sci Rep 2018; 8:11276. [PMID: 30050041 PMCID: PMC6062576 DOI: 10.1038/s41598-018-29310-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 07/09/2018] [Indexed: 02/07/2023] Open
Abstract
The infusion of hypertonic saline solution (HSS) is known to be beneficial to the treatment of hypovolemic hemorrhage (HH). The central mechanism of HSS-induced cardiovascular and autonomic recovery of animals subjected to HH remains unclear. Hence, the present study evaluated the involvement of median preoptic nucleus (MnPO) and medullary noradrenergic neurons (A1 and A2) in HSS-induced cardiovascular and sympathetic responses in hemorrhagic rats. The wistar rats were subjected to specific lesion of noradrenergic neurons through the nanoinjections of anti-DβH-saporin into caudal ventrolateral medulla (A1 neurons) and nucleus of the solitary tract (A2 neurons). After recovery, mean arterial pressure (MAP) and renal sympathetic nervous activity were recorded. The HH was performed through blood withdrawal until a MAP of 60 mmHg was attained. In sham rats, HSS infusion (3M NaCl) reestablished MAP without change in HH-induced sympathoinhibition. The muscimol (agonist of GABAA receptor) was nanoinjected in MnPO during HH and MnPO inhibition abolished the recovery of MAP and HSS-induced sympathoinhibition. Simultaneous lesions of A1 and A2 abolished MAP restoration and sympathoinhibition after HSS infusion. These results suggest that the recovery of MAP and HSS-induced sympathoinhibition in hemorrhaged rats depend on intact neural projections from A1 and A2 to MnPO.
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Affiliation(s)
- Lara Marques Naves
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Stefanne Madalena Marques
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Aline Andrade Mourão
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | | | - Carlos Henrique Xavier
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Carlos Henrique de Castro
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Ana Cristina Silva Rebelo
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Daniel Alves Rosa
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Rodrigo Mello Gomes
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil
| | - Eduardo Colombari
- Departamento de Fisiologia e Patologia, Faculdade de odontologia, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil
| | - Gustavo Rodrigues Pedrino
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Estrada do Campus, s/n, 74690-900, Goiânia, GO, Brazil.
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11
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Mourão AA, de Mello ABS, Dos Santos Moreira MC, Rodrigues KL, Lopes PR, Xavier CH, Gomes RM, Freiria-Oliveira AH, Blanch GT, Colombari E, Pedrino GR. Median preoptic nucleus excitatory neurotransmitters in the maintenance of hypertensive state. Brain Res Bull 2018; 142:207-215. [PMID: 29944948 DOI: 10.1016/j.brainresbull.2018.06.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 12/18/2022]
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.
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Affiliation(s)
- Aline A Mourão
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Aryanne B Soares de Mello
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Marina C Dos Santos Moreira
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Karla L Rodrigues
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Paulo R Lopes
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Carlos H Xavier
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Rodrigo M Gomes
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - André H Freiria-Oliveira
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil
| | - Graziela T Blanch
- School of Medicine, Pharmacy and Biomedicine, Pontifical Catholic University of Goias, Goiania, GO, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, São Paulo, Brazil
| | - Gustavo R Pedrino
- Center for Neuroscience and Cardiovascular Research, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiania, GO, Brazil.
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Ruchaya PJ, Speretta GF, Blanch GT, Li H, Sumners C, Menani JV, Colombari E, Colombari DSA. Overexpression of AT2R in the solitary-vagal complex improves baroreflex in the spontaneously hypertensive rat. Neuropeptides 2016; 60:29-36. [PMID: 27469059 DOI: 10.1016/j.npep.2016.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/20/2016] [Accepted: 06/05/2016] [Indexed: 02/07/2023]
Abstract
The aim of this study was to investigate the physiological effects of increased angiotensin II type 2 receptor (AT2R) expression in the solitary-vagal complex (nucleus of the solitary tract/dorsal motor nucleus of the vagus; NTS/DVM) on baroreflex function in non-anaesthetised normotensive (NT) and spontaneously hypertensive rats (SHR). Ten week old NT Holtzman and SHR were microinjected with either an adeno-associated virus expressing AT2R (AAV2-CBA-AT2R) or enhanced green fluorescent protein (control; AAV2-CBA-eGFP) into the NTS/DVM. Baroreflex and telemetry recordings were performed on four experimental groups: 1) NTeGFP, 2) NTAT2R, 3) SHReGFP and 4) SHRAT2R (n=4-7/group). Following in-vivo experimental procedures, brains were harvested for gene expression analysis. Impaired bradycardia in SHReGFP was restored in SHR rats overexpressing AT2R in the NTS/DMV. mRNA levels of angiotensin converting enzyme decreased and angiotensin converting enzyme 2 increased in the NTS/DMV of SHRAT2R compared to SHReGFP. Increased levels of pro-inflammatory cytokine mRNA levels in the SHReGFP group also decreased in the SHRAT2R group. AT2R overexpression did not elicit any significant change in mean arterial pressure (MAP) in all groups from baseline to 4weeks post viral transfection. Both SHReGFP and SHRAT2R showed a significant elevation in MAP compared to the NTeGFP and NTAT2R groups. Increased AT2R expression within the NTS/DMV of SHR was effective at improving baroreflex function but not MAP. We propose possible mediators involved in improving baroreflex are in the ANG II/ACE2 axis, suggesting a potential beneficial modulatory effect of AT2R overexpression in the NTS/DMV of neurogenic hypertensive rats.
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Affiliation(s)
- Prashant J Ruchaya
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil
| | - Guilherme F Speretta
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil
| | - Graziela Torres Blanch
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil
| | - Hongwei Li
- School of Biotechnology, Southern Medical University, Guangzhou, China
| | - Colin Sumners
- Department of Physiology and Functional Genomics and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, USA
| | - José V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil.
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil.
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Silva JN, Lucena EV, Silva TM, Damasceno RS, Takakura AC, Moreira TS. Inhibition of the pontine Kölliker-Fuse nucleus reduces genioglossal activity elicited by stimulation of the retrotrapezoid chemoreceptor neurons. Neuroscience 2016; 328:9-21. [PMID: 27126558 DOI: 10.1016/j.neuroscience.2016.04.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 04/16/2016] [Accepted: 04/18/2016] [Indexed: 01/06/2023]
Abstract
The Kölliker-Fuse (KF) region, located in the dorsolateral pons, projects to several brainstem areas involved in respiratory regulation, including the chemoreceptor neurons within the retrotrapezoid nucleus (RTN). Several lines of evidence indicate that the pontine KF region plays an important role in the control of the upper airways for the maintenance of appropriate airflow to and from the lungs. Specifically, we hypothesized that the KF region is involved in mediating the response of the hypoglossal motor activity to central respiratory chemoreflex activation and to stimulation of the chemoreceptor neurons within the RTN region. To test this hypothesis, we combined immunohistochemistry and physiological experiments. We found that in the KF, the majority of biotinylated dextran amine (BDA)-labeled axonal varicosities contained detectable levels of vesicular glutamate transporter-2 (VGLUT2), but few contained glutamic acid decarboxylase-67 (GAD67). The majority of the RTN neurons that were FluorGold (FG)-immunoreactive (i.e., projected to the KF) contained hypercapnia-induced Fos, but did not express tyrosine hydroxylase. In urethane-anesthetized sino-aortic denervated and vagotomized male Wistar rats, hypercapnia (10% CO2) or N-methyl-d-aspartate (NMDA) injection (0.1mM) in the RTN increased diaphragm (DiaEMG) and genioglossus muscle (GGEMG) activities and elicited abdominal (AbdEMG) activity. Bilateral injection of muscimol (GABA-A agonist; 2mM) into the KF region reduced the increase in DiaEMG and GGEMG produced by hypercapnia or NMDA into the RTN. Our data suggest that activation of chemoreceptor neurons in the RTN produces a significant increase in the genioglossus muscle activity and the excitatory pathway is dependent on the neurons located in the dorsolateral pontine KF region.
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Affiliation(s)
- Josiane N Silva
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo/SP, Brazil
| | - Elvis V Lucena
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo/SP, Brazil
| | - Talita M Silva
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo/SP, Brazil
| | - Rosélia S Damasceno
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo/SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo/SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo/SP, Brazil.
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Does the median preoptic nucleus contribute to sympathetic hyperactivity in spontaneously hypertensive rats? Auton Neurosci 2016; 195:29-33. [DOI: 10.1016/j.autneu.2016.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/08/2015] [Accepted: 02/16/2016] [Indexed: 02/04/2023]
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Damasceno RS, Takakura AC, Moreira TS. Regulation of the chemosensory control of breathing by Kölliker-Fuse neurons. Am J Physiol Regul Integr Comp Physiol 2014; 307:R57-67. [PMID: 24760995 DOI: 10.1152/ajpregu.00024.2014] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Kölliker-Fuse region (KF) and the lateral parabrachial nucleus (LPBN) have been implicated in the maintenance of cardiorespiratory control. Here, we evaluated the involvement of the KF region and the LPBN in cardiorespiratory responses elicited by chemoreceptor activation in unanesthetized rats. Male Wistar rats (280-330 g; n = 5-9/group) with bilateral stainless-steel guide cannulas implanted in the KF region or the LPBN were used. Injection of muscimol (100 and 200 pmol/100 nl) in the KF region decreased resting ventilation (1,140 ± 68 and 978 ± 100 vs. saline: 1,436 ± 155 ml·kg(-1)·min(-1)), without changing mean arterial pressure (MAP) and heart rate (HR). Bilateral injection of the GABA-A antagonist bicuculline (1 nmol/100 nl) in the KF blocked the inhibitory effect on ventilation (1,418 ± 138 vs. muscimol: 978 ± 100 ml·kg(-1)·min(-1)) elicited by muscimol. Muscimol injection in the KF reduced the increase in ventilation produced by hypoxia (8% O2) (1,827 ± 61 vs. saline: 3,179 ± 325 ml·kg(-1)·min(-1)) or hypercapnia (7% CO2) (1,488 ± 277 vs. saline: 3,539 ± 374 ml·kg(-1)·min(-1)) in unanesthetized rats. Bilateral injection of bicuculline in the KF blocked the decrease in ventilation produced by muscimol in the KF during peripheral or central chemoreflex activation. Bilateral injection of muscimol in the LPBN did not change resting ventilation or the increase in ventilation elicited by hypoxia or hypercapnia. The results of the present study suggest that the KF region, but not the LPBN, has mechanisms to control ventilation in resting, hypoxic, or hypercapnic conditions in unanesthetized rats.
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Affiliation(s)
- Rosélia S Damasceno
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil; and
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil; and
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Vieira AA, Colombari E, De Luca LA, Colombari DSA, De Paula PM, Menani JV. Cardiovascular responses to injections of angiotensin II or carbachol into the rostral ventrolateral medulla in rats with AV3V lesions. Neurosci Lett 2013; 556:32-6. [PMID: 24095671 DOI: 10.1016/j.neulet.2013.09.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 11/25/2022]
Abstract
Injection of l-glutamate (GLU) into the rostral ventrolateral medulla (RVLM) produces sympathetically-mediated pressor responses that depend on the integrity of the tissue surrounding the anteroventral third ventricle (AV3V region). The injection of angiotensin II (ANG II) or the cholinergic agonist carbachol into the RVLM also produces pressor responses. In the present study, we investigated if the lesion of the AV3V region affects the pressor responses to ANG II or carbachol injected into the RVLM in unanesthetized rats. Male Holtzman rats with sham or electrolytic AV3V lesions and a stainless steel cannula implanted into the RVLM were used. The pressor responses to ANG II (200ng/100nl) injected into the RVLM were reduced by acute (1 day) (12±3 vs. sham lesions: 26±4mmHg) or chronic (15 days) AV3V lesions (12±5 vs. sham lesions: 27±4mmHg), whereas acute or chronic AV3V lesions did not affect the pressor responses to carbachol (1nmol/100nl) injected into the RVLM. The present results suggest that the AV3V region modulates the excitability of the RVLM neurons involved with the pressor response produced by the activation of angiotensinergic mechanisms in this area.
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Affiliation(s)
- Alexandre Antonio Vieira
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP 14801-903, Brazil.
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Totola L, Alves T, Takakura A, Ferreira-Neto H, Antunes V, Menani J, Colombari E, Moreira T. Commissural nucleus of the solitary tract regulates the antihypertensive effects elicited by moxonidine. Neuroscience 2013; 250:80-91. [DOI: 10.1016/j.neuroscience.2013.06.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 06/28/2013] [Indexed: 01/28/2023]
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Moreira TS, Menani JV, Colombari E, Takakura AC. Is carotid body input the only critical mechanism involved in hypertension in spontaneously hypertensive rat? J Physiol 2013; 591:745-6. [PMID: 23378425 PMCID: PMC3577552 DOI: 10.1113/jphysiol.2012.244640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Blanch GT, Freiria-Oliveira AH, Murphy D, Paulin RF, Antunes-Rodrigues J, Colombari E, Menani JV, Colombari DSA. Inhibitory mechanism of the nucleus of the solitary tract involved in the control of cardiovascular, dipsogenic, hormonal, and renal responses to hyperosmolality. Am J Physiol Regul Integr Comp Physiol 2013; 304:R531-42. [PMID: 23364528 DOI: 10.1152/ajpregu.00191.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleus of the solitary tract (NTS) is the primary site of visceral afferents to the central nervous system. In the present study, we investigated the effects of lesions in the commissural portion of the NTS (commNTS) on the activity of vasopressinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, plasma vasopressin, arterial pressure, water intake, and sodium excretion in rats with plasma hyperosmolality produced by intragastric 2 M NaCl (2 ml/rat). Male Holtzman rats with 15-20 days of sham or electrolytic lesion (1 mA; 10 s) of the commNTS were used. CommNTS lesions enhanced a 2 M NaCl intragastrically induced increase in the number of vasopressinergic neurons expressing c-Fos in the PVN (28 ± 1, vs. sham: 22 ± 2 c-Fos/AVP cells) and SON (26 ± 4, vs. sham: 11 ± 1 c-Fos/AVP cells), plasma vasopressin levels (21 ± 8, vs. sham: 6.6 ± 1.3 pg/ml), pressor responses (25 ± 7 mmHg, vs. sham: 7 ± 2 mmHg), water intake (17.5 ± 0.8, vs. sham: 11.2 ± 1.8 ml/2 h), and natriuresis (4.9 ± 0.8, vs. sham: 1.4 ± 0.3 meq/1 h). The pretreatment with vasopressin antagonist abolished the pressor response to intragastric 2 M NaCl in commNTS-lesioned rats (8 ± 2.4 mmHg at 10 min), suggesting that this response is dependent on vasopressin secretion. The results suggest that inhibitory mechanisms dependent on commNTS act to limit or counterbalance behavioral, hormonal, cardiovascular, and renal responses to an acute increase in plasma osmolality.
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Affiliation(s)
- Graziela T Blanch
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, São Paulo, Brazil
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Freiria-Oliveira AH, Blanch GT, Li H, Colombari E, Colombari DSA, Sumners C. Macrophage migration inhibitory factor in the nucleus of solitary tract decreases blood pressure in SHRs. Cardiovasc Res 2012; 97:153-60. [PMID: 22997157 DOI: 10.1093/cvr/cvs297] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The macrophage migration inhibitory factor (MIF) is an intracellular inhibitor of the central nervous system actions of angiotensin II on blood pressure. Considering that angiotensin II actions at the nucleus of the solitary tract are important for the maintenance of hypertension in spontaneously hypertensive rats (SHRs), we tested if increased MIF expression in the nucleus of the solitary tract of SHR alters the baseline high blood pressure in these rats. METHODS AND RESULTS Eight-week-old SHRs or normotensive rats were microinjected with the vector AAV2-CBA-MIF into the nucleus of the solitary tract, resulting in MIF expression predominantly in neurons. Rats also underwent recordings of the mean arterial blood pressure (MAP) and heart rate (via telemetry devices implanted in the abdominal aorta), cardiac- and baroreflex function. Injections of AAV2-CBA-MIF into the nucleus of the solitary tract of SHRs produced significant decreases in the MAP, ranging from 10 to 20 mmHg, compared with age-matched SHRs that had received identical microinjections of the control vector AAV2-CBA-eGFP. This lowered MAP in SHRs was maintained through the end of the experiment at 31 days, and was associated with an improvement in baroreflex function to values observed in normotensive rats. In contrast to SHRs, similar increased MIF expression in the nucleus of the solitary tract of normotensive rats produced no changes in baseline MAP and baroreflex function. CONCLUSION These results indicate that an increased expression of MIF within the nucleus of the solitary tract neurons of SHRs lowers blood pressure and restores baroreflex function.
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Affiliation(s)
- André Henrique Freiria-Oliveira
- Department of Physiology and Functional Genomics and McKnight Brain Institute, College of Medicine, University of Florida, 1600 Southwest Archer Road, PO-BOX: 100274, Gainesville, FL 32610, USA
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Takakura AC, Moreira TS, De Paula PM, Menani JV, Colombari E. Control of breathing and blood pressure by parafacial neurons in conscious rats. Exp Physiol 2012; 98:304-15. [DOI: 10.1113/expphysiol.2012.065128] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Issa AT, Miyata K, Heng V, Mitchell KD, Derbenev AV. Increased neuronal activity in the OVLT of Cyp1a1-Ren2 transgenic rats with inducible Ang II-dependent malignant hypertension. Neurosci Lett 2012; 519:26-30. [PMID: 22579820 DOI: 10.1016/j.neulet.2012.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 04/27/2012] [Accepted: 05/02/2012] [Indexed: 11/27/2022]
Abstract
The contribution of angiotensin II (Ang II) to the pathophysiology of hypertension is established based on facts that high levels of circulating Ang II increase vasoconstriction of peripheral arteries causing a rise in blood pressure (BP). In addition, circulating Ang II has various effects on the central nervous system, including the osmosensitive neurons in the organum vasculosum of the lamina terminalis (OVLT). Osmosensitive neurons in the OVLT transduce hypertonicity via the activation of the nonselective cation channel known as transient receptor potential vanilloid 1 (TRPV1), causing membrane depolarization, followed by increased action potential discharge. This effect is absent in mice lacking expression of the TRPV1 gene. Most observations related to the importance of the OVLT in cardiovascular control are mainly based on models of lesion of the entire preoptic periventricular tissue. However, it remains unclear whether neuronal activity and TRPV1 protein expression levels alter in the OVLT of Cyp1a1-Ren2 transgenic rats with inducible Ang II-dependent malignant hypertension. C-fos was used as a marker of neuronal activity. Immunostaining was used to demonstrate distribution of c-fos positive neurons in the OVLT of Cyp1a1Ren2 transgenic rats. Western blot analysis showed increased c-fos and TRPV1 total protein expression levels in the OVLT of hypertensive rats. The present findings demonstrate increased c-fos and TRPV1 expression levels in the OVLT of Cyp1a1-Ren2 transgenic rats with Ang II-dependent malignant hypertension.
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Affiliation(s)
- Alexandra T Issa
- Department of Physiology, Tulane University, New Orleans, LA, United States
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Favero MT, Takakura AC, de Paula PM, Colombari E, Menani JV, Moreira TS. Chemosensory control by commissural nucleus of the solitary tract in rats. Respir Physiol Neurobiol 2011; 179:227-34. [PMID: 21884826 DOI: 10.1016/j.resp.2011.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/17/2011] [Accepted: 08/18/2011] [Indexed: 11/30/2022]
Abstract
The commissural nucleus of the solitary tract (commNTS) is a main area that receives afferent signals involved in the cardiovascular and respiratory control like those related to chemoreceptor activation, however, the importance of the commNTS for the cardiorespiratory responses to chemoreceptor activation is still controversial. In the present study, we investigated the cardiorespiratory responses to hypoxia or hypercapnia in anesthetized and conscious rats treated with injections of the GABA-A agonist muscimol into the caudal portion of the commNTS. Male Holtzman rats (280-300 g) were used. In conscious rats that had a stainless steel cannula previously implanted into the commNTS, the injection of muscimol (2 mM) into the commNTS reduced the pressor response (16±2 mmHg, vs. saline: 36±3 mmHg) and the increase in ventilation (250±17 ml/min/kg, vs. saline: 641±28 ml/min/kg) produced by hypoxia (8-10% O(2)). In urethane anesthetized rats, the injection of muscimol into the commNTS eliminated the pressor response (5±2 mmHg, vs. saline: 26±5 mmHg) and the increase in phrenic nerve discharge (PND) (20±6%, vs. saline: 149±15%) and reduced the increase in splanchnic sympathetic nerve discharge (sSND) (93±15%, vs. saline: 283±19% of baseline) produced by hypoxia. However, muscimol injected into the commNTS did not change hypercapnia (8-10% CO(2)) induced pressor response or the increase in the sSND or PND in urethane anesthetized rats or the increase in ventilation in conscious rats. The present results suggest that the cardiorespiratory responses to hypoxia are strongly dependent on the caudal portion of the commNTS, however, this area is not involved in the responses to hypercapnia.
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Affiliation(s)
- Michele T Favero
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
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Moreira TS, Takakura AC, Colombari E. Important GABAergic mechanism within the NTS and the control of sympathetic baroreflex in SHR. Auton Neurosci 2011; 159:62-70. [DOI: 10.1016/j.autneu.2010.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 07/17/2010] [Accepted: 08/10/2010] [Indexed: 02/07/2023]
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Ai J, Wang LH, Zhang R, Qiao GF, Wang N, Sun LH, Lu GY, Sun C, Yang BF. Protective effect of the daming capsule on impaired baroreflexes in STZ-induced diabetic rats with hyperlipoidemia. Altern Ther Health Med 2010; 10:80. [PMID: 21176164 PMCID: PMC3022895 DOI: 10.1186/1472-6882-10-80] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 12/22/2010] [Indexed: 11/12/2022]
Abstract
Background The Daming capsule (DMC) is a traditional Chinese medicine used to treat hyperlipoidemia. Both clinic trials and studies on animal models have demonstrated that DMC is beneficial against diabetic symptoms. Impairment of the baroreflex can cause life-threatening arrhythmias and sudden cardiac death in patients with diabetes mellitus (DM). This study was designed to elucidate the effects of DMC on baroreflexes in streptozocin (STZ)-induced diabetic rats with hyperlipoidemia. Methods Wistar rats were randomly divided into three groups: untreated controls, rats pretreated STZ and high lipids (a diabetes model or DM rats), and DM rats treated with DMC. The baroreflex sensitivity was examined during intravenous injection of phenylephrine (PE) or sodium nitroprusside (SNP) and quantified by the change in heart rate over the change in mean arterial blood pressure (ΔHR/ΔMABP). Morphological remodeling of baroreceptors was analyzed by transmission electron microscopy (TEM). The mRNA levels and expression of GluR2 and a GABAA receptor subunit were measured by quantitative RT-PCR and Western blotting. Results Compared to untreated DM rats, DMC significantly elevated the ratio of ΔHR/ΔMABP by enhancing the compensatory reduction in HR (-ΔHR) in response to PE-induced hypertension (+ΔMABP) (P < 0.05). In the presence of SNP, DMC increased the ΔMABP (P < 0.05). In addition, DMC markedly shortened the duration of blood pressure changes elicited by PE or SNP in DM rats compared to the untreated DM group (P < 0.05). Electron microscopy revealed disrupted myelin sheaths, swollen ER, and lysed mitochondria in the nucleus ambiguous (NAm) DM rats. These signs of neuropathology were largely prevented by treatment with DMC for 30 days. Treatment with DMC elevated both mRNA and protein level of GluR2 in the NAm of DM rats, but had no effect on GABAA receptor expression. Conclusion The Daming capsule partially reversed the parasympathetic baroreflex impairment observed in STZ-induced diabetic rats with hyperlipoidemia. Treatment with DMC also prevented the degeneration of neurons and myelinated axons in the brain stem NAm and reversed the down-regulation of GluR2 mRNA. Rescue of NAm function may contribute to the medicinal properties of DMC in diabetic rats.
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Vieira AA, Nahey DB, Collister JP. Role of the organum vasculosum of the lamina terminalis for the chronic cardiovascular effects produced by endogenous and exogenous ANG II in conscious rats. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1564-71. [DOI: 10.1152/ajpregu.00034.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endogenous and exogenous circulating ANG II acts at one of the central circumventricular organs (CVOs), the subfornical organ (SFO), to modulate chronic blood pressure regulation. However, at the forebrain, another important CVO is the organum vasculosum of the lamina terminalis (OVLT). In the present study, we tested the hypothesis that the OVLT mediates the hypertension or the hypotension produced by chronic infusion of ANG II or losartan (AT1 antagonist), respectively. Six days after sham or OVLT electrolytic lesion, male Sprague-Dawley rats (280–320 g, n = 6 per group) were instrumented with intravenous catheters and radiotelemetric blood pressure transducers. Following another week of recovery, rats were given 3 days of saline control infusion (7 ml/day) and were then infused with ANG II (10 ng·kg−1·min−1) or losartan (10 mg·kg−1·day−1) for 10 days, followed by 3 recovery days. Twenty-four hour average measurements of mean arterial pressure (MAP) and heart rate (HR) were made during this protocol. Hydromineral balance (HB) responses were measured during the experimental protocol. By day 9 of ANG II treatment, MAP had increased 16 ± 4 mmHg in sham rats but only 4 ± 1 mmHg in OVLT lesioned rats without changes in HR or HB. However, the hypotension produced by 10 days of losartan infusion was not modified in OVLT lesioned rats. These results suggest that the OVLT might play an important role during elevation of plasma ANG II, facilitating increases of blood pressure but is not involved with baseline effects of endogenous ANG II.
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Affiliation(s)
- Alexandre A. Vieira
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
| | - David B. Nahey
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
| | - John P. Collister
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
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Kobori H, Fu Q, Crowley SD, Gonzalez-Villalobos RA, Campos RR. Comments on Point:Counterpoint: The dominant contributor to systemic hypertension: Chronic activation of the sympathetic nervous system vs. Activation of the intrarenal renin-angiotensin system. Activated intrarenal renin-angiotensin system is correlated with high blood pressure in humans. J Appl Physiol (1985) 2010; 109:2003. [PMID: 21148352 PMCID: PMC3774210 DOI: 10.1152/japplphysiol.01160.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Hiroyuki Kobori
- Department of Medicine, Tulane University Health Sciences Center, LA, USA
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