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Pernomian L, Waigi EW, Nguyen V, Mohammed AD, da Costa TJ, Fontes MT, Kubinak JL, Aitken A, Biancardi VC, Sinclair DA, McCarthy CG, Wang Y, Tan W, Wenceslau CF. A Single-Short Partial Reprogramming of the Endothelial Cells decreases Blood Pressure via attenuation of EndMT in Hypertensive Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.595057. [PMID: 38826452 PMCID: PMC11142064 DOI: 10.1101/2024.05.20.595057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Background Small artery remodeling and endothelial dysfunction are hallmarks of hypertension. Growing evidence supports a likely causal association between cardiovascular diseases and the presence of endothelial-to-mesenchymal transition (EndMT), a cellular transdifferentiation process in which endothelial cells (ECs) partially lose their identity and acquire additional mesenchymal phenotypes. EC reprogramming represents an innovative strategy in regenerative medicine to prevent deleterious effects induced by cardiovascular diseases. Methods Using a partial reprogramming of ECs, via overexpression of Oct-3/4, Sox-2, and Klf-4 (OSK) transcription factors, we aimed to bring ECs back to a youthful phenotype in hypertensive mice. Primary ECs were infected with lentiviral vectors (LV) containing the specific EC marker cadherin 5 (Cdh5) and the fluorescent reporter enhanced green fluorescence protein (EGFP) with empty vector (LVCO) or with OSK (LV-OSK). Confocal microscopy and western blotting analysis were used to confirm the OSK overexpression. Cellular migration, senescence, and apoptosis were evaluated. Human aortic ECs (HAoECs) from male and female normotensive and hypertensive patients were analyzed after OSK or control treatments for their endothelial nitric oxide synthase (eNOS) levels, nitric oxide (NO), and genetic profile. Male and female normotensive (BPN/3J) and hypertensive (BPH/2J) mice were treated with an intravenous (i.v.) injection of LVCO or LV-OSK and evaluated 10 days post-infection. The blood pressure, cardiac function, vascular reactivity of small arteries, in vivo EGFP signal and EndMT inhibition were analyzed. Results OSK overexpression induced partial EC reprogramming in vitro , and these cells showed endothelial progenitor cell (EPC)-like features with lower migratory capability. OSK treatment of hypertensive BPH/2J mice normalized blood pressure and resistance arteries hypercontractility, via the attenuation of EndMT and elastin breaks. EGFP signal was detected in vivo in the prefrontal cortex of both BPN/3J and BPH/2J-treated mice, but OSK induced angiogenesis only in male BPN/3J mice. OSK-treated human ECs from hypertensive patients showed high eNOS activation and NO production, with low ROS formation. Single-cell RNA analysis showed that OSK alleviated EC senescence and EndMT, restoring their phenotypes in human ECs from hypertensive patients. Conclusion Overall, these data indicate that OSK treatment and EC reprogramming can decrease blood pressure and reverse hypertension-induced vascular damage.
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Shin H, Sharma R, Neupane C, Pham TL, Park SE, Lee SY, Kim HW, Bae YM, Stern JE, Park JB. Tonic NMDAR Currents of NR2A-Containing NMDARs Represent Altered Ambient Glutamate Concentration in the Supraoptic Nucleus. eNeuro 2024; 11:ENEURO.0279-23.2023. [PMID: 38176904 PMCID: PMC10863629 DOI: 10.1523/eneuro.0279-23.2023] [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: 07/26/2023] [Revised: 12/03/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
NMDA receptors (NMDARs) modulate glutamatergic excitatory tone in the brain via two complementary modalities: a phasic excitatory postsynaptic current and a tonic extrasynaptic modality. Here, we demonstrated that the tonic NMDAR-current (I NMDA) mediated by NR2A-containing NMDARs is an efficient biosensor detecting the altered ambient glutamate level in the supraoptic nucleus (SON). I NMDA of magnocellular neurosecretory cells (MNCs) measured by nonselective NMDARs antagonist, AP5, at holding potential (V holding) -70 mV in low concentration of ECF Mg2+ ([Mg2+]o) was transiently but significantly increased 1-week post induction of a DOCA salt hypertensive model rat which was compatible with that induced by a NR2A-selective antagonist, PEAQX (I PEAQX) in both DOCA-H2O and DOCA-salt groups. In agreement, NR2B antagonist, ifenprodil, or NR2C/D antagonist, PPDA, did not affect the holding current (I holding) at V holding -70 mV. Increased ambient glutamate by exogenous glutamate (10 mM) or excitatory amino acid transporters (EAATs) antagonist (TBOA, 50 mM) abolished the I PEAQX difference between two groups, suggesting that attenuated EAATs activity increased ambient glutamate concentration, leading to the larger I PEAQX in DOCA-salt rats. In contrast, only ifenprodil but not PEAQX and PPDA uncovered I NMDA at V holding +40 mV under 1.2 mM [Mg2+]o condition. I ifenprodil was not different in DOCA-H2O and DOCA-salt groups. Finally, NR2A, NR2B, and NR2D protein expression were not different in the SON of the two groups. Taken together, NR2A-containing NMDARs efficiently detected the increased ambient glutamate concentration in the SON of DOCA-salt hypertensive rats due to attenuated EAATs activity.
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Affiliation(s)
- Hyunjin Shin
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - Ramesh Sharma
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Chiranjivi Neupane
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Thuy Linh Pham
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - Su Eun Park
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyun-Woo Kim
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - Young Min Bae
- Department of Physiology, Konkuk University School of Medicine, Chungju 27478, Republic of Korea
| | - Javier E Stern
- Neuroscience Institute and Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30302
| | - Jin Bong Park
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
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Dellacqua LO, Gomes PM, Batista JS, Michelini LC, Antunes VR. Exercise-induced neuroplasticity in autonomic nuclei restores the cardiac vagal tone and baroreflex dysfunction in aged hypertensive rats. J Appl Physiol (1985) 2024; 136:189-198. [PMID: 38059293 DOI: 10.1152/japplphysiol.00433.2023] [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: 06/30/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023] Open
Abstract
Aging is accompanied by considerable deterioration of homeostatic systems, such as autonomic imbalance characterized by heightened sympathetic activity, lower parasympathetic tone, and depressed heart rate (HR) variability, which are aggravated by hypertension. Here, we hypothesized that these age-related deficits in aged hypertensive rats can be ameliorated by exercise training, with benefits to the cardiovascular system. Therefore, male 22-mo-old spontaneously hypertensive rats (SHRs) and age-matched Wistar Kyoto (WKY) submitted to moderate-intensity exercise training (T) or kept sedentary (S) for 8 wk were evaluated for hemodynamic/autonomic parameters, baroreflex sensitivity, cardiac sympathetic/parasympathetic tone and analysis of dopamine β-hydroxylase (DBH+) and oxytocin (OT+) pathways of autonomic brain nuclei. Aged SHR-S versus WKY-S exhibited elevated mean arterial pressure (MAP: +51%) and HR (+20%), augmented pressure/HR variability, no cardiac vagal tone, and depressed reflex control of the heart (HR range, -28%; gain, -49%). SHR-T exhibited a lower resting HR, a partial reduction in the MAP (-14%), in the pressure/HR variabilities, and restored parasympathetic modulation, with improvement of baroreceptor reflex control when compared with SHR-S. Exercise training increased the ascending DBH+ projections conveying peripheral information to the paraventricular nucleus of hypothalamus (PVN), augmented the expression of OT+ neurons, and reduced the density of DBH+ neurons in the rostral ventrolateral medulla (RVLM) of SHR-T. Data indicate that exercise training induces beneficial neuroplasticity in brain autonomic circuitry, and it is highly effective to restore the parasympathetic tone, and attenuation of age-related autonomic imbalance and baroreflex dysfunction, thus conferring long-term benefits for cardiovascular control in aged hypertensive individuals.NEW & NOTEWORTHY Exercise training reduces high blood pressure and cardiovascular autonomic modulation in aged hypertensive rats. The dysfunction in the baroreflex sensitivity and impaired parasympathetic tone to the heart of aged hypertensive rats are restored by exercise training. Exercise induces beneficial neuroplasticity in the brain nuclei involved with autonomic control of cardiovascular function of aged hypertensive rats.
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Affiliation(s)
- Lais Oliveira Dellacqua
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Paula Magalhães Gomes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Julia Santos Batista
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Lisete Compagno Michelini
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Vagner Roberto Antunes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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Makrygianni EA, Chrousos GP. Neural Progenitor Cells and the Hypothalamus. Cells 2023; 12:1822. [PMID: 37508487 PMCID: PMC10378393 DOI: 10.3390/cells12141822] [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: 03/02/2023] [Revised: 05/22/2023] [Accepted: 06/02/2023] [Indexed: 07/30/2023] Open
Abstract
Neural progenitor cells (NPCs) are multipotent neural stem cells (NSCs) capable of self-renewing and differentiating into neurons, astrocytes and oligodendrocytes. In the postnatal/adult brain, NPCs are primarily located in the subventricular zone (SVZ) of the lateral ventricles (LVs) and subgranular zone (SGZ) of the hippocampal dentate gyrus (DG). There is evidence that NPCs are also present in the postnatal/adult hypothalamus, a highly conserved brain region involved in the regulation of core homeostatic processes, such as feeding, metabolism, reproduction, neuroendocrine integration and autonomic output. In the rodent postnatal/adult hypothalamus, NPCs mainly comprise different subtypes of tanycytes lining the wall of the 3rd ventricle. In the postnatal/adult human hypothalamus, the neurogenic niche is constituted by tanycytes at the floor of the 3rd ventricle, ependymal cells and ribbon cells (showing a gap-and-ribbon organization similar to that in the SVZ), as well as suprachiasmatic cells. We speculate that in the postnatal/adult human hypothalamus, neurogenesis occurs in a highly complex, exquisitely sophisticated neurogenic niche consisting of at least four subniches; this structure has a key role in the regulation of extrahypothalamic neurogenesis, and hypothalamic and extrahypothalamic neural circuits, partly through the release of neurotransmitters, neuropeptides, extracellular vesicles (EVs) and non-coding RNAs (ncRNAs).
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Affiliation(s)
- Evanthia A Makrygianni
- University Research Institute of Maternal and Child Health & Precision Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - George P Chrousos
- University Research Institute of Maternal and Child Health & Precision Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
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Milanez MIO, Nishi EE, Mendes R, Rocha AA, Bergamaschi CT, Campos RR. Renal sympathetic activation triggered by the rostral ventrolateral medulla is dependent of spinal cord AT1 receptors in Goldblatt hypertensive rats. Peptides 2021; 146:170660. [PMID: 34571055 DOI: 10.1016/j.peptides.2021.170660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 11/20/2022]
Abstract
Spinal cord neurons contribute to elevated sympathetic vasomotor activity in renovascular hypertension (2K1C), particularly, increased actions of angiotensin II. However, the origin of these spinal angiotensinergic inputs remains unclear. The present study aimed to investigate the role of spinal angiotensin II type 1 receptor (AT1) receptors in the sympathoexcitatory responses evoked by the activation of the rostral ventrolateral medulla (RVLM) in control and 2K1C Goldblatt rats. Hypertension was induced by clipping of the left renal artery. After 6 weeks, a catheter (PE-10) filled with losartan was inserted into the subarachnoid space and advanced to the T10-11 vertebral level in urethane-anesthetized rats. The effects of glutamate microinjection into the RVLM on blood pressure (BP), heart rate (HR), and renal and splanchnic sympathetic nerve activity (rSNA and sSNA, respectively) were evaluated in the presence or absence of spinal AT1 blockade. Tachycardic, pressor, and renal sympathoexcitatory effects caused by RVLM activation were significantly blunted by losartan in 2K1C rats, but not in control rats. However, no differences were found in the gene expression of angiotensin-converting enzyme, angiotensinogen, and renin in the spinal cord segments between the groups. In conclusion, acute sympathoexcitation induced by RVLM activation is dependent on the spinal AT1 receptor in Goldblatt, but not in control, rats. The involvement of other central cardiovascular nuclei in spinal angiotensinergic actions, as well as the source of angiotensin II, remains to be determined in the Goldblatt model.
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Affiliation(s)
- Maycon I O Milanez
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Erika E Nishi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Rodrigo Mendes
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Antônio A Rocha
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Cássia T Bergamaschi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Ruy R Campos
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
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Marins FR, Limborço-Filho M, Iddings JA, Xavier CH, Biancardi VC, Stern JE, Ramiro Diaz J, Oppenheimer SM, Filosa JA, Peliky Fontes MA. Tachycardia evoked from insular stroke in rats is dependent on glutamatergic neurotransmission in the dorsomedial hypothalamus. Eur J Neurol 2021; 28:3640-3649. [PMID: 34152065 DOI: 10.1111/ene.14987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND PURPOSE Damage to the insula results in cardiovascular complications. In rats, activation of N-methyl-d-aspartate receptors (NMDARs) in the intermediate region of the posterior insular cortex (iIC) results in sympathoexcitation, tachycardia and arterial pressure increases. Similarly, focal experimental hemorrhage at the iIC results in a marked sympathetic-mediated increase in baseline heart rate. The dorsomedial hypothalamic region (DMH) is critical for the integration of sympathetic-mediated tachycardic responses. Here, whether responses evoked from the iIC are dependent on a synaptic relay in the DMH was evaluated. METHODS Wistar rats were prepared for injections into the iIC and DMH. Anatomical (tracing combined with immunofluorescence) and functional experiments (cardiovascular and sympathetic recordings) were performed. RESULTS The iIC sends dense projections to the DMH. Approximately 50% of iIC neurons projecting to the DMH express NMDARs, NR1 subunit. Blockade of glutamatergic receptors in the DMH abolishes the cardiovascular and autonomic responses evoked by the activation of NMDARs in the iIC (change in mean arterial pressure 7 ± 1 vs. 1 ± 1 mmHg after DMH blockade; change in heart rate 28 ± 3 vs. 0 ± 3 bpm after DMH blockade; change in renal sympathetic nerve activity 23% ± 1% vs. -1% ± 4% after DMH blockade). Experimental hemorrhage at the iIC resulted in a marked tachycardia (change 89 ± 14 bpm) that was attenuated by 65% ± 5% (p = 0.0009) after glutamatergic blockade at the DMH. CONCLUSIONS The iIC-induced tachycardia is largely dependent upon a glutamatergic relay in the DMH. Our study reveals the presence of an excitatory glutamatergic pathway from the iIC to the DMH that may be involved in the cardiovascular alterations observed after insular stroke.
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Affiliation(s)
- Fernanda Ribeiro Marins
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Marcelo Limborço-Filho
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Carlos Henrique Xavier
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Brazil
| | - Vinicia C Biancardi
- Department of Anatomy, Physiology, and Pharmacology, Auburn University, and Center for Neurosciences Research Initiative, Auburn University, Auburn, AL, USA
| | - Javier E Stern
- Department of Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | - Stephen M Oppenheimer
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Abstract
Neuroanatomic and functional studies show the paraventricular (PVN) of the hypothalamus to have a central role in the autonomic control that supports cardiovascular regulation. Direct and indirect projections from the PVN preautonomic neurons to the sympathetic preganglionic neurons in the spinal cord modulate sympathetic activity. The preautonomic neurons of the PVN adjust their level of activation in response to afferent signals arising from peripheral viscerosensory receptors relayed through the nucleus tractus solitarius. The prevailing sympathetic tone is a balance between excitatory and inhibitory influences that arises from the preautonomic PVN neurons. Under physiologic conditions, tonic sympathetic inhibition driven by a nitric oxide-γ-aminobutyric acid-mediated mechanism is dominant, but in pathologic situation such as heart failure there is a switch from inhibition to sympathoexcitation driven by glutamate and angiotensin II. Angiotensin II, reactive oxygen species, and hypoxia as a result of myocardial infarction/ischemia alter the tightly regulated posttranslational protein-protein interaction of CAPON (carboxy-terminal postsynaptic density protein ligand of neuronal nitric oxide synthase (NOS1)) and PIN (protein inhibitor of NOS1) signaling mechanism. Within the preautonomic neurons of the PVN, the disruption of CAPON and PIN signaling leads to a downregulation of NOS1 expression and reduced NO bioavailability. These data support the notion that CAPON-PIN dysregulation of NO bioavailability is a major contributor to the pathogenesis of sympathoexcitation in heart failure.
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Affiliation(s)
- Susan Pyner
- Department of Biosciences, Durham University, Durham, United Kingdom.
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Milanez MIO, Veiga AC, Martins BS, Pontes RB, Bergamaschi CT, Campos RR, Nishi EE. Renal Sensory Activity Regulates the γ-Aminobutyric Acidergic Inputs to the Paraventricular Nucleus of the Hypothalamus in Goldblatt Hypertension. Front Physiol 2020; 11:601237. [PMID: 33384613 PMCID: PMC7769809 DOI: 10.3389/fphys.2020.601237] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/27/2020] [Indexed: 12/27/2022] Open
Abstract
Renal sensory activity is centrally integrated within brain nuclei involved in the control of cardiovascular function, suggesting that renal afferents regulate basal and reflex sympathetic vasomotor activity. Evidence has shown that renal deafferentation (DAx) evokes a hypotensive and sympathoinhibitory effect in experimental models of cardiovascular diseases; however, the underlying mechanisms involved in this phenomenon need to be clarified, especially those related to central aspects. We aimed to investigate the role of renal afferents in the control of γ-aminobutyric acid (GABA)ergic inputs to the paraventricular nucleus (PVN) of the hypothalamus in renovascular hypertensive (2K1C) rats and their influence in the regulation of cardiovascular function. Hypertension was induced by clipping the left renal artery. After 4 weeks, renal DAx was performed by exposing the left renal nerve to a 33 mM capsaicin solution for 15 min. After 2 weeks of DAx, microinjection of muscimol into the PVN was performed in order to evaluate the influence of GABAergic activity in the PVN and its contribution to the control of renal sympathetic nerve activity (rSNA) and blood pressure (BP). Muscimol microinjected into the PVN triggered a higher drop in BP and rSNA in the 2K1C rats and renal DAx mitigated these responses. These results suggest that renal afferents are involved in the GABAergic changes found in the PVN of 2K1C rats. Although the functional significance of this phenomenon needs to be clarified, it is reasonable to speculate that GABAergic alterations occur to mitigate microglia activation-induced sympathoexcitation in the PVN of 2K1C rats.
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Affiliation(s)
- Maycon I O Milanez
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Amanda C Veiga
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Beatriz S Martins
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Roberto B Pontes
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Cassia T Bergamaschi
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ruy R Campos
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Erika E Nishi
- Department of Physiology, Cardiovascular Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Milanez MIO, Nishi EE, Bergamaschi CT, Campos RR. Role of spinal neurons in the maintenance of elevated sympathetic activity: a novel therapeutic target? Am J Physiol Regul Integr Comp Physiol 2020; 319:R282-R287. [DOI: 10.1152/ajpregu.00122.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The control of sympathetic vasomotor activity involves a complex network within the brain and spinal circuits. An extensive range of studies has indicated that sympathoexcitation is a common feature in several cardiovascular diseases and that strategies to reduce sympathetic vasomotor overactivity in such conditions can be beneficial. In the present mini-review, we present evidence supporting the spinal cord as a potential therapeutic target to mitigate sympathetic vasomotor overactivity in cardiovascular diseases, focusing mainly on the actions of spinal angiotensin II on the control of sympathetic preganglionic neuronal activity.
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Affiliation(s)
- Maycon I. O. Milanez
- Cardiovascular Physiology Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Sao Paulo, Brazil
| | - Erika E. Nishi
- Cardiovascular Physiology Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Sao Paulo, Brazil
| | - Cássia T. Bergamaschi
- Cardiovascular Physiology Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Sao Paulo, Brazil
| | - Ruy R. Campos
- Cardiovascular Physiology Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Sao Paulo, Brazil
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Li Y, Yu R, Zhang D, Yang W, Hou Q, Li Y, Jiang H. Deciphering the Mechanism of the Anti-Hypertensive Effect of Isorhynchophylline by Targeting Neurotransmitters Metabolism of Hypothalamus in Spontaneously Hypertensive Rats. ACS Chem Neurosci 2020; 11:1563-1572. [PMID: 32356970 DOI: 10.1021/acschemneuro.9b00699] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Essential hypertension is a major risk factor for cardiovascular disease that can lead eventually to structural and functional alterations in the brain. Accumulating evidence has suggested that the increased activities in renin-angiotensin system and sympathetic nerve participated in the pathogenesis of hypertension that is related to the imbalance between neurotransmitters. The potential role in essential hypertension arising from alterations of neurotransmitters in the central nervous system remains understudied. Isorhynchophylline is a major oxindole alkaloid extracted from Uncaria rhynchophylla, which has been widely used for treating hypertension and neurodegenerative diseases. Whether isorhynchophylline acts on neurotransmitters to lower blood pressure has been hypothesized but rarely demonstrated unequivocally. Here, we studied the metabolic neurotransmitter profiles in the hypothalamus using a targeted metabolomic approach in spontaneously hypertensive rats after isorhynchophylline intervention. Our study demonstrated that isorhynchophylline exhibited a strong anti-hypertensive effect in spontaneously hypertensive rats by improving the neurotransmitter imbalance in the hypothalamus and inhibiting the overactivation of the renin-angiotensin system and sympathetic nerve system. Overall, this study played an essential role in enhancing our understanding of the mechanism of isorhynchophylline in essential hypertension and in providing theoretical evidence for future research and clinical application.
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Affiliation(s)
- Yuan Li
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Key Laboratory of Traditional Chinese Medicine Classical Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Shandong Provincial Key Laboratory of Traditional Chinese Medicine for Basic Research, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Ruixue Yu
- College of Pharmaceutical Sciences, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong China
| | - Dan Zhang
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Key Laboratory of Traditional Chinese Medicine Classical Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Shandong Provincial Key Laboratory of Traditional Chinese Medicine for Basic Research, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Wenqing Yang
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Key Laboratory of Traditional Chinese Medicine Classical Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Shandong Provincial Key Laboratory of Traditional Chinese Medicine for Basic Research, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Qingqing Hou
- College of Pharmaceutical Sciences, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong China
| | - Yunlun Li
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Traditional Chinese Medicine Clinical Research Base for Hypertension, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan 250011, Shandong, China
| | - Haiqiang Jiang
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Key Laboratory of Traditional Chinese Medicine Classical Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
- Shandong Provincial Key Laboratory of Traditional Chinese Medicine for Basic Research, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
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Milanez MIO, Nishi EE, Rocha AA, Bergamaschi CT, Campos RR. Interaction between angiotensin II and GABA in the spinal cord regulates sympathetic vasomotor activity in Goldblatt hypertension. Neurosci Lett 2020; 728:134976. [PMID: 32304717 DOI: 10.1016/j.neulet.2020.134976] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/17/2020] [Accepted: 04/07/2020] [Indexed: 12/16/2022]
Abstract
Previous studies have been described changes in brain regions contributing to the sympathetic vasomotor overactivity in Goldblatt hypertension (2K1C). Furthermore, changes in the spinal cord are also involved in the cardiovascular and autonomic dysfunction in renovascular hypertension, as intrathecal (i.t.) administration of Losartan (Los) causes a robust hypotensive/sympathoinhibitory response in 2K1C but not in control rats. The present study evaluated the role of spinal γ-aminobutyric acid (GABA)-ergic inputs in the control of sympathetic vasomotor activity in the 2K1C rats. Hypertension was induced by clipping the renal artery. After six weeks, a catheter (PE-10) was inserted into the subarachnoid space and advanced to the T10-11 vertebral level in urethane-anaesthetized rats. The effects of i.t. injection of bicuculline (Bic) on blood pressure (BP), renal and splanchnic sympathetic nerve activity (rSNA and sSNA, respectively) were evaluated over 40 consecutive minutes in the presence or absence of spinal AT1 antagonism. I.t. Bic triggered a more intense pressor and sympathoexcitatory response in 2K1C rats, however, these responses were attenuated by previous i.t. Los. No differences in the gene expression of GAD 65 and GABA-A receptors subunits in the spinal cord segments were found. Thus, the sympathoexcitation induced by spinal GABA-A blockade is dependent of local AT1 receptor in 2K1C but not in control rats. Excitatory angiotensinergic inputs to sympathetic preganglionic neurons are tonic controlled by spinal GABAergic actions in Goldblatt hypertension.
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Affiliation(s)
- Maycon I O Milanez
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Erika E Nishi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Antônio A Rocha
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Cássia T Bergamaschi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Ruy R Campos
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
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12
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Japundžić-Žigon N, Lozić M, Šarenac O, Murphy D. Vasopressin & Oxytocin in Control of the Cardiovascular System: An Updated Review. Curr Neuropharmacol 2020; 18:14-33. [PMID: 31544693 PMCID: PMC7327933 DOI: 10.2174/1570159x17666190717150501] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/03/2019] [Accepted: 07/06/2019] [Indexed: 01/19/2023] Open
Abstract
Since the discovery of vasopressin (VP) and oxytocin (OT) in 1953, considerable knowledge has been gathered about their roles in cardiovascular homeostasis. Unraveling VP vasoconstrictor properties and V1a receptors in blood vessels generated powerful hemostatic drugs and drugs effective in the treatment of certain forms of circulatory collapse (shock). Recognition of the key role of VP in water balance via renal V2 receptors gave birth to aquaretic drugs found to be useful in advanced stages of congestive heart failure. There are still unexplored actions of VP and OT on the cardiovascular system, both at the periphery and in the brain that may open new venues in treatment of cardiovascular diseases. After a brief overview on VP, OT and their peripheral action on the cardiovascular system, this review focuses on newly discovered hypothalamic mechanisms involved in neurogenic control of the circulation in stress and disease.
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Affiliation(s)
| | - Maja Lozić
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Olivera Šarenac
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
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13
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Díaz HS, Toledo C, Andrade DC, Marcus NJ, Del Rio R. Neuroinflammation in heart failure: new insights for an old disease. J Physiol 2020; 598:33-59. [PMID: 31671478 DOI: 10.1113/jp278864] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/09/2019] [Indexed: 08/25/2023] Open
Abstract
Heart failure (HF) is a complex clinical syndrome affecting roughly 26 million people worldwide. Increased sympathetic drive is a hallmark of HF and is associated with disease progression and higher mortality risk. Several mechanisms contribute to enhanced sympathetic activity in HF, but these pathways are still incompletely understood. Previous work suggests that inflammation and activation of the renin-angiotensin system (RAS) increases sympathetic drive. Importantly, chronic inflammation in several brain regions is commonly observed in aged populations, and a growing body of evidence suggests neuroinflammation plays a crucial role in HF. In animal models of HF, central inhibition of RAS and pro-inflammatory cytokines normalizes sympathetic drive and improves cardiac function. The precise molecular and cellular mechanisms that lead to neuroinflammation and its effect on HF progression remain undetermined. This review summarizes the most recent advances in the field of neuroinflammation and autonomic control in HF. In addition, it focuses on cellular and molecular mediators of neuroinflammation in HF and in particular on brain regions involved in sympathetic control. Finally, we will comment on what is known about neuroinflammation in the context of preserved vs. reduced ejection fraction HF.
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Affiliation(s)
- Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA, USA
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
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14
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Sharma NM, Liu X, Llewellyn TL, Katsurada K, Patel KP. Exercise training augments neuronal nitric oxide synthase dimerization in the paraventricular nucleus of rats with chronic heart failure. Nitric Oxide 2019; 87:73-82. [PMID: 30878404 PMCID: PMC6527363 DOI: 10.1016/j.niox.2019.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/06/2019] [Accepted: 03/08/2019] [Indexed: 12/20/2022]
Abstract
Exercise training (ExT) is an established non-pharmacological therapy that improves the health and quality of life in patients with chronic heart failure (CHF). Exaggerated sympathetic drive characterizes CHF due to an imbalance of the autonomic nervous system. Neuronal nitric oxide synthase (nNOS) in the paraventricular nucleus (PVN) produce nitric oxide (NO•), which is known to regulate the sympathetic tone. Previously we have shown that during CHF, the catalytically active dimeric form of nNOS is significantly decreased with a concurrent increase in protein inhibitor of nNOS (PIN) expression, a protein that dissociates dimeric nNOS to monomers and facilitates its degradation. Dimerization of nNOS also requires (6R)-5,6,7,8-tetrahydrobiopterin (BH4) for stability and activity. Previously, we have shown that ExT improves NO-mediated sympathetic inhibition in the PVN; however, the molecular mechanism remains elusive. We hypothesized; ExT restores the sympathetic drive by increasing the levels and catalytically active form of nNOS by abrogating changes in the PIN in the PVN of CHF rats. CHF was induced in adult male Sprague-Dawley rats by coronary artery ligation, which reliably mimics CHF in patients with myocardial infarction. After 4 weeks of surgery, Sham and CHF rats were subjected to 3 weeks of progressive treadmill exercise. ExT significantly (p < 0.05) decreased PIN expression and increased dimer/monomer ratio of nNOS in the PVN of rats with CHF. Moreover, we found decreased GTP cyclohydrolase 1(GCH1) expression: a rate-limiting enzyme for BH4 biosynthesis in the PVN of CHF rats suggesting that perhaps reduced BH4 availability may also contribute to decreased nNOS dimers. Interestingly, CHF induced decrease in GCH1 expression was increased with ExT. Our findings revealed that ExT rectified decreased PIN and GCH1 expression and increased dimer/monomer ratio of nNOS in the PVN, which may lead to increase NO• bioavailability resulting in amelioration of activated sympathetic drive during CHF.
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Affiliation(s)
- Neeru M Sharma
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA.
| | - Xuefei Liu
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
| | - Tamra L Llewellyn
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
| | - Kenichi Katsurada
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
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15
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Breton JM, Charbit AR, Snyder BJ, Fong PTK, Dias EV, Himmels P, Lock H, Margolis EB. Relative contributions and mapping of ventral tegmental area dopamine and GABA neurons by projection target in the rat. J Comp Neurol 2018; 527:916-941. [PMID: 30393861 DOI: 10.1002/cne.24572] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/08/2018] [Accepted: 10/21/2018] [Indexed: 12/12/2022]
Abstract
The ventral tegmental area (VTA) is a heterogeneous midbrain structure that contains dopamine (DA), GABA, and glutamate neurons that project to many different brain regions. Here, we combined retrograde tracing with immunocytochemistry against tyrosine hydroxylase (TH) or glutamate decarboxylase (GAD) to systematically compare the proportion of dopaminergic and GABAergic VTA projections to 10 target nuclei: anterior cingulate, prelimbic, and infralimbic cortex; nucleus accumbens core, medial shell, and lateral shell; anterior and posterior basolateral amygdala; ventral pallidum; and periaqueductal gray. Overall, the non-dopaminergic component predominated VTA efferents, accounting for more than 50% of all projecting neurons to each region except the nucleus accumbens core. In addition, GABA neurons contributed no more than 20% to each projection, with the exception of the projection to the ventrolateral periaqueductal gray, where the GABAergic contribution approached 50%. Therefore, there is likely a significant glutamatergic component to many of the VTA's projections. We also found that VTA cell bodies retrogradely labeled from the various target brain regions had distinct distribution patterns within the VTA, including in the locations of DA and GABA neurons. Despite this patterned organization, VTA neurons comprising these different projections were intermingled and never limited to any one subregion. These anatomical results are consistent with the idea that VTA neurons participate in multiple distinct, parallel circuits that differentially contribute to motivation and reward. While attention has largely focused on VTA DA neurons, a better understanding of VTA subpopulations, especially the contribution of non-DA neurons to projections, will be critical for future work.
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Affiliation(s)
- Jocelyn M Breton
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California
| | - Annabelle R Charbit
- Department of Neurology and Wheeler Center for the Neurobiology of Addiction, University of California, San Francisco, California
| | - Benjamin J Snyder
- Department of Neurology and Wheeler Center for the Neurobiology of Addiction, University of California, San Francisco, California
| | - Peter T K Fong
- Department of Neurology and Wheeler Center for the Neurobiology of Addiction, University of California, San Francisco, California.,Ernest Gallo Clinic and Research Center, University of California, San Francisco, Emeryville, California
| | - Elayne V Dias
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, Emeryville, California
| | - Patricia Himmels
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, Emeryville, California
| | - Hagar Lock
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, Emeryville, California
| | - Elyssa B Margolis
- Department of Neurology and Wheeler Center for the Neurobiology of Addiction, University of California, San Francisco, California.,Ernest Gallo Clinic and Research Center, University of California, San Francisco, Emeryville, California
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16
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Impaired Hypothalamic Regulation of Sympathetic Outflow in Primary Hypertension. Neurosci Bull 2018; 35:124-132. [PMID: 30506315 DOI: 10.1007/s12264-018-0316-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 11/01/2018] [Indexed: 01/01/2023] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) is a crucial region involved in maintaining homeostasis through the regulation of cardiovascular, neuroendocrine, and other functions. The PVN provides a dominant source of excitatory drive to the sympathetic outflow through innervation of the brainstem and spinal cord in hypertension. We discuss current findings on the role of the PVN in the regulation of sympathetic output in both normotensive and hypertensive conditions. The PVN seems to play a major role in generating the elevated sympathetic vasomotor activity that is characteristic of multiple forms of hypertension, including primary hypertension in humans. Recent studies in the spontaneously hypertensive rat model have revealed an imbalance of inhibitory and excitatory synaptic inputs to PVN pre-sympathetic neurons as indicated by impaired inhibitory and enhanced excitatory synaptic inputs in hypertension. This imbalance of inhibitory and excitatory synaptic inputs in the PVN forms the basis for elevated sympathetic outflow in hypertension. In this review, we discuss the disruption of balance between glutamatergic and GABAergic inputs and the associated cellular and molecular alterations as mechanisms underlying the hyperactivity of PVN pre-sympathetic neurons in hypertension.
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17
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Chronic Intracerebroventricular Infusion of Metformin Inhibits Salt-Sensitive Hypertension via Attenuation of Oxidative Stress and Neurohormonal Excitation in Rat Paraventricular Nucleus. Neurosci Bull 2018; 35:57-66. [PMID: 30426340 DOI: 10.1007/s12264-018-0308-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 09/26/2018] [Indexed: 01/15/2023] Open
Abstract
Metformin (MET), an antidiabetic agent, also has antioxidative effects in metabolic-related hypertension. This study was designed to determine whether MET has anti-hypertensive effects in salt-sensitive hypertensive rats by inhibiting oxidative stress in the hypothalamic paraventricular nucleus (PVN). Salt-sensitive rats received a high-salt (HS) diet to induce hypertension, or a normal-salt (NS) diet as control. At the same time, they received intracerebroventricular (ICV) infusion of MET or vehicle for 6 weeks. We found that HS rats had higher oxidative stress levels and mean arterial pressure (MAP) than NS rats. ICV infusion of MET attenuated MAP and reduced plasma norepinephrine levels in HS rats. It also decreased reactive oxygen species and the expression of subunits of NAD(P)H oxidase, improved the superoxide dismutase activity, reduced components of the renin-angiotensin system, and altered neurotransmitters in the PVN. Our findings suggest that central MET administration lowers MAP in salt-sensitive hypertension via attenuating oxidative stress, inhibiting the renin-angiotensin system, and restoring the balance between excitatory and inhibitory neurotransmitters in the PVN.
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18
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Control of renal sympathetic nerve activity by neurotransmitters in the spinal cord in Goldblatt hypertension. Brain Res 2018; 1698:43-53. [PMID: 29935157 DOI: 10.1016/j.brainres.2018.06.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 05/25/2018] [Accepted: 06/19/2018] [Indexed: 11/20/2022]
Abstract
The role of spinal cord neurons in renal sympathoexcitation remains unclear in renovascular hypertension, represented by the 2-kidney, 1-clip (2K1C) model. Thus, we aimed to assess the influence of spinal glutamatergic and AT1 angiotensin II receptors on renal sympathetic nerve activity (rSNA) in 2K1C Wistar rats. Hypertension was induced by clipping the renal artery with a silver clip. After six weeks, a catheter (PE-10) was inserted into the subarachnoid space and advanced to the T10-11 vertebral level in urethane-anaesthetized rats. The effects of intrathecally (i.t.) injected kynurenic acid (KYN) or losartan (Los) on blood pressure (BP) and rSNA were analysed over 2 consecutive hours. KYN induced a significantly larger drop in rSNA among 2K1C rats than among control (CTL) rats (CTL vs. 2K1C: -8 ± 3 vs. -52 ± 9 spikes/s after 120'). Los also evoked a significantly larger drop in rSNA among 2K1C rats than among CTL rats starting at 80' after administration (CTL vs. 2K1C - 80 min: -10 ± 2 vs. -32 ± 6∗; 100 min: -15 ± 4 vs. -37 ± 9∗; 120 min: -12 ± 5 vs. -37 ± 8∗ spikes/s). KYN decreased BP similarly in the CTL and 2K1C groups; however, Los significantly decreased BP in the 2K1C group only. We found upregulation of AT1 gene expression in the T11-12 spinal segments in the 2K1C group but no change in gene expression for AT2 or ionotropic glutamate (NMDA, kainate and AMPA) receptors. Thus, our data show that spinal ionotropic glutamatergic and AT1 receptors contribute to increased rSNA in the 2K1C model, leading to the maintenance of hypertension; however, the participation of spinal AT1 receptors seems to be especially important in the establishment of sympathoexcitation in this model. The origins of those projections, i.e., the brain areas involved in establishing the activity of spinal glutamatergic and angiotensinergic pathways, remain unclear.
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19
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Santos CR, Ruggeri A, Ceroni A, Michelini LC. Exercise training abrogates age-dependent loss of hypothalamic oxytocinergic circuitry and maintains high parasympathetic activity. J Neuroendocrinol 2018; 30:e12601. [PMID: 29656427 DOI: 10.1111/jne.12601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 04/05/2018] [Indexed: 11/27/2022]
Abstract
Neuroanatomical studies associating neuronal tract tracing and immunohistochemistry identified reciprocal (ascending noradrenergic/descending oxytocinergic, OTergic) connections between brainstem cardiovascular nuclei and the paraventricular hypothalamic nucleus (PVN). Previous functional studies indicated that exercise training (T) augmented the expression/activity of OTergic pathway and improve the autonomic control of the heart. Knowing that ageing is associated with autonomic dysfunction and sinoaortic denervation blocked T-induced beneficial effects, we hypothesized that T was able to reduce age-dependent impairment by improving the afferent signaling to PVN and augmenting OTergic modulation of cardiovascular control. We evaluated the combined effects of T and age on plastic remodeling of ascending dopamine β-hydroxylase (DBH+) and descending OT+ pathways and correlated them with cardiovascular parameters. Male Wistar rats were submitted to T or kept sedentary for 8 weeks. After evaluating arterial pressure, heart rate (HR), their variabilities and spectral components in conscious rats at rest, brains were harvested to analyze the plastic remodeling of brain autonomic nuclei (immunofluorescence + confocal microscopy). The density of DBH+ neurons within the nucleus of solitary tract (NTS) and caudal ventrolateral medulla, the number of DBH+ terminals overlapping OT+ neurons in PVN preautonomic nuclei, as well as the density of OT+ neurons and their projections to NTS and dorsal motor nucleus of the vagus were markedly reduced in S rats during 8-weeks of inactivity In contrast, these effects were completely blocked by T and reversed to a large augmentation of DBH+ and OT+ densities in both cell bodies and terminals within autonomic nuclei and target areas. All plastic changes observed correlated positively with parasympathetic activity to the heart (HF-PI, but not with LF-PI) and negatively with resting HR. Data indicate that T, by increasing beneficial neuroplastic adaptive changes within brainstem-PVN reciprocal network, abrogates age-dependent deleterious remodeling and augments parasympathetic modulation of the heart, therefore improving autonomic function. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Carla R Santos
- Department of Physiology, Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo/SP, Brazil
| | - Adriana Ruggeri
- Department of Physiology, Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo/SP, Brazil
| | - Alexandre Ceroni
- Department of Physiology, Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo/SP, Brazil
| | - Lisete C Michelini
- Department of Physiology, Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo/SP, Brazil
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20
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Jiang E, Chapp AD, Fan Y, Larson RA, Hahka T, Huber MJ, Yan J, Chen QH, Shan Z. Expression of Proinflammatory Cytokines Is Upregulated in the Hypothalamic Paraventricular Nucleus of Dahl Salt-Sensitive Hypertensive Rats. Front Physiol 2018. [PMID: 29520237 PMCID: PMC5826963 DOI: 10.3389/fphys.2018.00104] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Accumulating evidence indicates that inflammation is implicated in hypertension. However, the role of brain proinflammatory cytokines (PICs) in salt sensitive hypertension remains to be determined. Thus, the objective of this study was to test the hypothesis that high salt (HS) diet increases PICs expression in the paraventricular nucleus (PVN) and leads to PVN neuronal activation. Eight-week-old male Dahl salt sensitive (Dahl S) rats, and age and sex matched normal Sprague Dawley (SD) rats were divided into two groups and fed with either a HS (4% NaCl) or normal salt (NS, 0.4% NaCl) diet for 5 consecutive weeks. HS diet induced hypertension and significantly increased cerebrospinal fluid (CSF) sodium concentration ([Na+]) in Dahl S rats, but not in normal SD rats. In addition, HS diet intake triggered increases in mRNA levels and immunoreactivities of PVN PICs including TNF-α, IL-6, and IL-1β, as well as Fra1, a chronic marker of neuronal activation, in Dahl S rats, but not in SD rats. Next, we investigated whether this increase in the expression of PVN PICs and Fra1 was induced by increased CSF [Na+]. Adult male SD rats were intracerebroventricular (ICV) infused with 8 μl of either hypertonic salt (4 μmol NaCl), mannitol (8 μmol, as osmolarity control), or isotonic salt (0.9% NaCl as vehicle control). Three hours following the ICV infusion, rats were euthanized and their PVN PICs expression was measured. The results showed that central administration of hypertonic saline in SD rats significantly increased the expression of PICs including TNF-α, IL-6, and IL-1β, as well as neuronal activation marker Fra1, compared to isotonic NaCl controls and osmolarity controls. Finally, we tested whether the increase in PICs expression occurred in neurons. Incubation of hypothalamic neurons with 10 mM NaCl in a culture medium for 6 h elicited significant increases in TNF-α, IL-6, and Fra1 mRNA levels. These observations, coupled with the important role of PICs in modulating neuronal activity and stimulating vasopressin release, suggest that HS intake induces an inflammatory state in the PVN, which, may in turn, augments sympathetic nerve activity and vasopressin secretion, contributing to the development of salt sensitive hypertension.
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Affiliation(s)
- Enshe Jiang
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Institute for Nursing and Health Research, Henan University, Kaifeng, China
| | - Andrew D Chapp
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Yuanyuan Fan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Robert A Larson
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Taija Hahka
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Michael J Huber
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Jianqun Yan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
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21
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Liang B, Zhao YN, Wang X, Yu XJ, Li Y, Yang HY, Su Q, Kang YM, Yang ZM. Angiotensin-(1-7) attenuates hypertension and cardiac hypertrophy via modulation of nitric oxide and neurotransmitter levels in the paraventricular nucleus in salt-sensitive hypertensive rats. RSC Adv 2018; 8:8779-8786. [PMID: 35547241 PMCID: PMC9087825 DOI: 10.1039/c7ra09136b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 02/15/2018] [Indexed: 01/15/2023] Open
Abstract
Angiotensin-(1-7) [Ang-(1-7)] is a multifunctional bioactive angiotensin peptide which exerts a cardiovascular protective function mainly by opposing the effects of angiotensin II. We aimed to determine whether brain Ang-(1-7) regulates nitric oxide (NO) and neurotransmitter levels in the hypothalamic paraventricular nucleus (PVN), and influences sympathetic activity, blood pressure and cardiac hypertrophy in salt-sensitive hypertension. Dahl salt-sensitive rats receiving a high-salt (HS, 8% NaCl) or a normal-salt (NS, 0.3% NaCl) diet were treated with an intracerebroventricular (ICV) infusion of Ang-(1-7) for 6 weeks. Seven rats were measured in each group. In comparison with NS rats, HS rats exhibited significantly increased mean arterial pressure, plasma norepinephrine (NE) and cardiac hypertrophy. In addition, HS rats (compared to NS rats) had increased glutamate, NE and tyrosine hydroxylase (TH) expression, and reduced NO levels as well as reduced expression of γ-aminobutyric acid (GABA) and the 67 kDa isoform of glutamate decarboxylase (GAD67) in the PVN. Treatment with ICV infusion of Ang-(1-7) reversed these changes in the salt-sensitive hypertensive rats. The results suggest that the beneficial effects of brain Ang-(1-7) on salt-sensitive hypertension and cardiac hypertrophy are partly due to an elevation in the NO level and restoration of neurotransmitter balance in the PVN. Angiotensin-(1-7) [Ang-(1-7)] is a multifunctional bioactive angiotensin peptide which exerts a cardiovascular protective function mainly by opposing the effects of angiotensin II.![]()
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Affiliation(s)
- Bin Liang
- Department of Cardiology
- The Second Hospital of Shanxi Medical University
- Taiyuan 030001
- China
- Key Laboratory of Cardiovascular Medicine and Clinical Pharmacology of Shanxi Province
| | - Ya-Nan Zhao
- Department of Cardiology
- The Second Hospital of Shanxi Medical University
- Taiyuan 030001
- China
- Department of Respiratory
| | - Xin Wang
- Key Laboratory of Cardiovascular Medicine and Clinical Pharmacology of Shanxi Province
- Taiyuan 030001
- China
| | - Xiao-Jing Yu
- Department of Physiology and Pathophysiology
- Xi'an Jiaotong University School of Basic Medical Sciences
- Xi'an Jiaotong University Health Science Center
- Xi'an 710061
- China
| | - Ying Li
- Department of Physiology and Pathophysiology
- Xi'an Jiaotong University School of Basic Medical Sciences
- Xi'an Jiaotong University Health Science Center
- Xi'an 710061
- China
| | - Hui-Yu Yang
- Department of Cardiology
- The Second Hospital of Shanxi Medical University
- Taiyuan 030001
- China
- Key Laboratory of Cardiovascular Medicine and Clinical Pharmacology of Shanxi Province
| | - Qing Su
- Department of Physiology and Pathophysiology
- Xi'an Jiaotong University School of Basic Medical Sciences
- Xi'an Jiaotong University Health Science Center
- Xi'an 710061
- China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology
- Xi'an Jiaotong University School of Basic Medical Sciences
- Xi'an Jiaotong University Health Science Center
- Xi'an 710061
- China
| | - Zhi-Ming Yang
- Department of Cardiology
- The Second Hospital of Shanxi Medical University
- Taiyuan 030001
- China
- Key Laboratory of Cardiovascular Medicine and Clinical Pharmacology of Shanxi Province
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Shen Z, Weng C, Zhang Z, Wang X, Yang K. Renal sympathetic denervation lowers arterial pressure in canines with obesity-induced hypertension by regulating GAD65 and AT 1R expression in rostral ventrolateral medulla. Clin Exp Hypertens 2017; 40:49-57. [PMID: 29172730 DOI: 10.1080/10641963.2017.1306542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To explore the roles of glutamate acid decarboxylase 65 (GAD65) and angiotensin II type 1 receptor (AT1R) in the action of renal sympathetic denervation (RSD) on obesity-induced hypertension in canines. Thirty-two beagles were randomly divided into a hypertensive model (n = 22) and control (n = 10) groups. A hypertensive canine model was established by feeding a high-fat diet. Twenty hypertensive beagles were randomized equally to a sham-surgery and RSD-treated group receiving catheter-based radiofrequency RSD. Compared with the control group, the sham-surgery group exhibited significant increases in blood pressure, serum angiotensin II level, rostral ventrolateral medulla (RVLM) glutamate level, and AT1R mRNA and protein expression and decreases in γ-amino acid butyric acid (γ-GABA) level and GAD65 mRNA and protein expression in the RVLM (all P < 0.05). Treatment with RSD significantly attenuated the above abnormal alterations (all P < 0.05). Linear correlation analysis revealed that angiotensin II level was positively correlated with glutamate level (r = 0.804) and inversely correlated with γ-GABA level (r = -0.765). GAD65 protein expression was positively correlated with γ-GABA level (r = 0.782). Catheter-based radiofrequency RSD can decrease blood pressure in obesity-induced hypertensive canines. The antihypertensive mechanism might be linked to upregulation of GAD65 and downregulation of AT1R in the RVLM.
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Affiliation(s)
- Zhijie Shen
- a Department of Cardiology , The Third Xiangya Hospital of Central South University , Changsha , China
| | - Chunyan Weng
- a Department of Cardiology , The Third Xiangya Hospital of Central South University , Changsha , China
| | - Zhihui Zhang
- a Department of Cardiology , The Third Xiangya Hospital of Central South University , Changsha , China
| | - Xiaoyan Wang
- a Department of Cardiology , The Third Xiangya Hospital of Central South University , Changsha , China
| | - Kan Yang
- a Department of Cardiology , The Third Xiangya Hospital of Central South University , Changsha , China
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Zhang M, Stern JE. Altered NMDA receptor-evoked intracellular Ca 2+ dynamics in magnocellular neurosecretory neurons of hypertensive rats. J Physiol 2017; 595:7399-7411. [PMID: 29034474 DOI: 10.1113/jp275169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/03/2017] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS NMDA receptor (NMDAR)-mediated Ca2+ signalling plays a critical role in modulating hypothalamic neurosecretory function. However, whether an altered NMDAR-evoked changes in Ca2+ (NMDAR-ΔCa2+ ) signalling in magnocellular neurosecretory cells (MNCs) may contribute to neurohumoral activation during disease states is unknown. We show that activation of NMDARs evoked similar inward currents in MNCs of sham and renovascular hypertensive (RVH) rats. Despite this, a prolonged and larger NMDAR-ΔCa2+ response was observed in the latter. The exacerbated NMDAR-ΔCa2+ responses in MNCs of RVH rats affected both somatic and dendritic compartments. Inhibition of the endoplasmic reticulum sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump prolonged NMDAR-ΔCa2+ responses in sham rats, but not in RVH rats. Our study supports an altered spatiotemporal dynamic of NMDAR-ΔCa2+ signalling in MNCs from RVH rats, partly due to blunted endoplasmic reticulum Ca2+ buffering capacity. ABSTRACT A growing body of evidence supports an elevated NMDA receptor (NMDAR)-mediated glutamate excitatory function in the supraoptic nucleus and paraventricular nucleus of hypertensive rats that contributes to neurohumoral activation in this disease. However, the precise mechanisms underlying altered NMDAR signalling in hypertension remain to be elucidated. In this study, we performed simultaneous electrophysiology and fast confocal Ca2+ imaging to determine whether altered NMDAR-mediated changes in intracellular Ca2+ levels (NMDAR-ΔCa2+ ) occurred in hypothalamic magnocellular neurosecretory cells (MNCs) in renovascular hypertensive (RVH) rats. We found that despite evoking a similar excitatory inward current, activation of NMDARs resulted in a larger and prolonged ΔCa2+ in MNCs from RVH rats. Changes in NMDAR-ΔCa2+ dynamics were observed both in somatic and dendritic compartments. Inhibition of the sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump activity with thapsigargin prolonged NMDAR-ΔCa2+ responses in MNCs of sham rats, but this effect was occluded in RVH rats, thus equalizing the magnitude and time course of the NMDA-ΔCa2+ responses between the two experimental groups. Taken together, our results support (1) an exacerbated NMDAR-ΔCa2+ response in somatodendritic compartments of MNCs of RVH rats, and (2) that a blunted ER Ca2+ buffering capacity contributes to the altered NMDAR-ΔCa2+ dynamics in this condition. Thus, altered spatiotemporal dynamics of the NMDAR-ΔCa2+ response stands as an underlying mechanism contributing to neurohumoral activation in neurogenic hypertension.
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Affiliation(s)
- Meng Zhang
- Department of Physiology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Javier E Stern
- Department of Physiology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
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Zhang M, Biancardi VC, Stern JE. An increased extrasynaptic NMDA tone inhibits A-type K + current and increases excitability of hypothalamic neurosecretory neurons in hypertensive rats. J Physiol 2017; 595:4647-4661. [PMID: 28378360 PMCID: PMC5509869 DOI: 10.1113/jp274327] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 03/31/2017] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS A functional coupling between extrasynaptic NMDA receptors (eNMDARs) and the A-type K+ current (IA ) influences homeostatic firing responses of magnocellular neurosecretory cells (MNCs) to a physiological challenge. However, whether an altered eNMDAR-IA coupling also contributes to exacerbated MNC activity and neurohumoral activation during disease states is unknown. We show that activation of eNMDARs by exogenously applied NMDA inhibited IA in MNCs obtained from sham, but not in MNCs from renovascular hypertensive (RVH) rats. Neither the magnitude of the exogenously evoked NMDA current nor the expression of NMDAR subunits were altered in RVH rats. Conversely, we found that a larger endogenous glutamate tone, which was not due to blunted glutamate transport activity, led to the sustained activation of eNMDARs that tonically inhibited IA , contributing in turn to higher firing activity in RVH rats. Our studies show that exacerbated activation of eNMDARs by endogenous glutamate contributes to tonic inhibition of IA and enhanced MNC excitability in RVH rats. ABSTRACT We recently showed that a functional coupling between extrasynaptic NMDA receptors (eNMDARs) and the A-type K+ current (IA ) influences the firing activity of hypothalamic magnocellular neurosecretory neurons (MNCs), as well as homeostatic adaptive responses to a physiological challenge. Here, we aimed to determine whether changes in the eNMDAR-IA coupling also contributed to exacerbated MNC activity during disease states. We used a combination of patch-clamp electrophysiology and real-time PCR in MNCs in sham and renovascular hypertensive (RVH) rats. Activation of eNMDARs by exogenously applied NMDA inhibited IA in sham rats, but this effect was largely blunted in RVH rats. The blunted response was not due to changes in eNMDAR expression and/or function, since neither NMDA current magnitude or reversal potential, nor the levels of NR1-NR2A-D subunit expression were altered in RVH rats. Conversely, we found a larger endogenous glutamate tone, resulting in the sustained activation of eNMDARs that tonically inhibited IA and contributed also to higher ongoing firing activity in RVH rats. The enhanced endogenous glutamate tone in RVH rats was not due to blunted glutamate transporter activity. Rather, a higher transporter activity was observed, which possibly acted as a compensatory mechanism in the face of the elevated endogenous tone. In summary, our studies indicate that an elevated endogenous glutamate tone results in an exacerbated activation of eNMDARs, which in turn contributes to diminished IA magnitude and increased firing activity of MNCs from hypertensive rats.
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Affiliation(s)
- Meng Zhang
- Department of PhysiologyMedical College of GeorgiaAugusta University1120 15th StreetAugustaGA30912USA
| | - Vinicia C. Biancardi
- Department of PhysiologyMedical College of GeorgiaAugusta University1120 15th StreetAugustaGA30912USA
| | - Javier E. Stern
- Department of PhysiologyMedical College of GeorgiaAugusta University1120 15th StreetAugustaGA30912USA
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25
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Dombrowski MD, Mueller PJ. Sedentary conditions and enhanced responses to GABA in the RVLM: role of the contralateral RVLM. Am J Physiol Regul Integr Comp Physiol 2017; 313:R158-R168. [PMID: 28490450 DOI: 10.1152/ajpregu.00366.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 05/08/2017] [Accepted: 05/08/2017] [Indexed: 02/07/2023]
Abstract
A sedentary lifestyle is a major risk factor for cardiovascular disease, and both conditions are associated with overactivity of the sympathetic nervous system. Ongoing discharge of sympathetic nerves is regulated by the rostral ventrolateral medulla (RVLM), which in turn is modulated by the primary excitatory and inhibitory neurotransmitters glutamate and γ-amino-butyric acid (GABA), respectively. We reported previously that sedentary conditions enhance GABAergic modulation of sympathoexcitation in the RVLM, despite overall increased sympathoexcitation. Thus the purpose of this study was to test the hypothesis that sedentary conditions increase responsiveness to GABA in RVLM. Male Sprague-Dawley rats performed either chronic wheeling running or remained sedentary for 12-15 wk. Animals were instrumented to perform RVLM microinjections under Inactin anesthesia while mean arterial pressure (MAP) and splanchnic sympathetic nerve activity (SSNA) were recorded. Unilateral microinjections of GABA (30 nl, 0.3-600 mM) into the RVLM produced dose-dependent decreases in MAP and SSNA; however, no group differences were observed. Inhibition of the contralateral RVLM (muscimol, 2 mM, 90 nl) caused decreases in MAP and SSNA that were not different between groups but enhanced decreases in SSNA to GABA in sedentary rats only. In sinoaortic denervated rats, GABA microinjections before or after inhibition of the contralateral RVLM caused decreases in MAP and SSNA that were not different between groups. Our results suggest that the contralateral RVLM plays an important role in buffering responses to inhibition of the ipsilateral RVLM under sedentary but not physically active conditions. Based on these studies and others, sedentary conditions appear to enhance both sympathoinhibitory and sympathoexcitatory mechanisms in the RVLM. Enhanced sympathoinhibition may act to reduce already elevated sympathetic nervous system activity following sedentary conditions.
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Affiliation(s)
- Maryetta D Dombrowski
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Patrick J Mueller
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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Marins FR, Iddings JA, Fontes MAP, Filosa JA. Evidence that remodeling of insular cortex neurovascular unit contributes to hypertension-related sympathoexcitation. Physiol Rep 2017; 5:e13156. [PMID: 28270592 PMCID: PMC5350170 DOI: 10.14814/phy2.13156] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 01/18/2017] [Indexed: 11/24/2022] Open
Abstract
The intermediate region of the posterior insular cortex (intermediate IC) mediates sympathoexcitatory responses to the heart and kidneys. Previous studies support hypertension-evoked changes to the structure and function of neurons, blood vessels, astrocytes and microglia, disrupting the organization of the neurovascular unit (NVU). In this study, we evaluated the functional and anatomical integrity of the NVU at the intermediate IC in the spontaneously hypertensive rat (SHR) and its control the Wistar-Kyoto (WKY). Under urethane anesthesia, NMDA microinjection (0.2 mmol/L/100 nL) was performed at the intermediate IC with simultaneous recording of renal sympathetic nerve activity (RSNA), heart rate (HR) and mean arterial pressure (MAP). Alterations in NVU structure were investigated by immunofluorescence for NMDA receptors (NR1), blood vessels (70 kDa FITC-dextran), astrocytes (GFAP), and microglia (Iba1). Injections of NMDA into intermediate IC of SHR evoked higher amplitude responses of RSNA, MAP, and HR On the other hand, NMDA receptor blockade decreased baseline RSNA, MAP and HR in SHR, with no changes in WKY Immunofluorescence data from SHR intermediate IC showed increased NMDA receptor density, contributing to the SHR enhanced sympathetic responses, and increased in vascular density (increased number of branches and endpoints, reduced average branch length), suggesting angiogenesis. Additionally, IC from SHR presented increased GFAP immunoreactivity and contact between astrocyte processes and blood vessels. In SHR, IC microglia skeleton analysis supports their activation (reduced number of branches, junctions, endpoints and process length), suggesting an inflammatory process in this region. These findings indicate that neurogenic hypertension in SHR is accompanied by marked alterations to the NVU within the IC and enhanced NMDA-mediated sympathoexcitatory responses likely contributors of the maintenance of hypertension.
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Affiliation(s)
- Fernanda R Marins
- Departamento de Fisiologia e Biofísica, INCT, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Marco A P Fontes
- Departamento de Fisiologia e Biofísica, INCT, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Paradoxical Sleep Deprivation Causes Cardiac Dysfunction and the Impairment Is Attenuated by Resistance Training. PLoS One 2016; 11:e0167029. [PMID: 27880816 PMCID: PMC5120843 DOI: 10.1371/journal.pone.0167029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 11/08/2016] [Indexed: 01/09/2023] Open
Abstract
Background Paradoxical sleep deprivation activates the sympathetic nervous system and the hypothalamus-pituitary-adrenal axis, subsequently interfering with the cardiovascular system. The beneficial effects of resistance training are related to hemodynamic, metabolic and hormonal homeostasis. We hypothesized that resistance training can prevent the cardiac remodeling and dysfunction caused by paradoxical sleep deprivation. Methods Male Wistar rats were distributed into four groups: control (C), resistance training (RT), paradoxical sleep deprivation for 96 hours (PSD96) and both resistance training and sleep deprivation (RT/PSD96). Doppler echocardiograms, hemodynamics measurements, cardiac histomorphometry, hormonal profile and molecular analysis were evaluated. Results Compared to the C group, PSD96 group had a higher left ventricular systolic pressure, heart rate and left atrium index. In contrast, the left ventricle systolic area and the left ventricle cavity diameter were reduced in the PSD96 group. Hypertrophy and fibrosis were also observed. Along with these alterations, reduced levels of serum testosterone and insulin-like growth factor-1 (IGF-1), as well as increased corticosterone and angiotensin II, were observed in the PSD96 group. Prophylactic resistance training attenuated most of these changes, except angiotensin II, fibrosis, heart rate and concentric remodeling of left ventricle, confirmed by the increased of NFATc3 and GATA-4, proteins involved in the pathologic cardiac hypertrophy pathway. Conclusions Resistance training effectively attenuates cardiac dysfunction and hormonal imbalance induced by paradoxical sleep deprivation.
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28
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Khanmoradi M, Nasimi A. Angiotensin II in the paraventricular nucleus stimulates sympathetic outflow to the cardiovascular system and make vasopressin release in rat. Neurosci Lett 2016; 632:98-103. [PMID: 27565052 DOI: 10.1016/j.neulet.2016.08.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN) plays essential roles in neuroendocrine and autonomic functions, including cardiovascular regulation. It was shown that microinjection of angiotensin II (AngII) into the PVN produced a pressor response. In this study, we explored the probable mechanisms of this pressor response. AngII was microinjected into the PVN and cardiovascular responses were recorded. Then, the responses were re-tested after systemic injection of a ganglionic blocker, Hexamethonium, or a vasopressin V1 receptor blocker. Hexamethonium pretreatment (i.v.) greatly and significantly attenuated the pressor response to AngII, with no significant effect on heart rate, indicating that the sympathetic system is involved in the cardiovascular effect of AngII in the PVN. Systemic pretreatment (i.v.) with V1 antagonist greatly and significantly attenuated the pressor response to AngII, with no significant effect on heart rate, indicating that vasopressin release is involved in the cardiovascular effect of AngII in the PVN. Overall, we found that AngII microinjected into the PVN produced a pressor response mediated by the sympathetic system and vasopressin release, indicating that other than circulating AngII, endogenous AngII of the PVN increases the vasopressin release from the PVN.
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Affiliation(s)
- Mehrangiz Khanmoradi
- Department of physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Ali Nasimi
- Department of physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
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29
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Pitra S, Feng Y, Stern JE. Mechanisms underlying prorenin actions on hypothalamic neurons implicated in cardiometabolic control. Mol Metab 2016; 5:858-868. [PMID: 27688999 PMCID: PMC5034613 DOI: 10.1016/j.molmet.2016.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 02/07/2023] Open
Abstract
Background Hypertension and obesity are highly interrelated diseases, being critical components of the metabolic syndrome. Despite the growing prevalence of this syndrome in the world population, efficient therapies are still missing. Thus, identification of novel targets and therapies are warranted. An enhanced activity of the hypothalamic renin-angiotensin system (RAS), including the recently discovered prorenin (PR) and its receptor (PRR), has been implicated as a common mechanism underlying aberrant sympatho-humoral activation that contributes to both metabolic and cardiovascular dysregulation in the metabolic syndrome. Still, the identification of precise neuronal targets, cellular mechanisms and signaling pathways underlying PR/PRR actions in cardiovascular- and metabolic related hypothalamic nuclei remain unknown. Methods and results Using a multidisciplinary approach including patch-clamp electrophysiology, live calcium imaging and immunohistochemistry, we aimed to elucidate cellular mechanisms underlying PR/PRR actions within the hypothalamic supraoptic (SON) and paraventricular nucleus (PVN), key brain areas previously involved in cardiometabolic regulation. We show for the first time that PRR is expressed in magnocellular neurosecretory cells (MNCs), and to a lesser extent, in presympathetic PVN neurons (PVNPS). Moreover, we show that while PRR activation efficiently stimulates the firing activity of both MNCs and PVNPS neurons, these effects involved AngII-independent and AngII-dependent mechanisms, respectively. In both cases however, PR excitatory effects involved an increase in intracellular Ca2+ levels and a Ca2+-dependent inhibition of a voltage-gated K+ current. Conclusions We identified novel neuronal targets and cellular mechanisms underlying PR/PRR actions in critical hypothalamic neurons involved in cardiometabolic regulation. This fundamental mechanistic information regarding central PR/PRR actions is essential for the development of novel RAS-based therapeutic targets for the treatment of cardiometabolic disorders in obesity and hypertension. PRR is expressed in SON and PVN neurosecretory and presympathetic neurons. PRR activation stimulates firing activity of SON and PVN neurons. PR/PRR effects on neurosecretory neurons are AngII-independent. PR/PRR effects on presympathetic neurons are AngII-dependent. PR inhibits a voltage-gated K+ current in a Ca2+-dependent manner.
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Affiliation(s)
- Soledad Pitra
- Department of Physiology, Medical College of Georgia, Augusta University, United States
| | - Yumei Feng
- Departments of Pharmacology, Physiology and Cell Biology, Center for Cardiovascular Research, University of Nevada School of Medicine, United States
| | - Javier E Stern
- Department of Physiology, Medical College of Georgia, Augusta University, United States.
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30
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Vagal afferents, sympathetic efferents and the role of the PVN in heart failure. Auton Neurosci 2016; 199:38-47. [DOI: 10.1016/j.autneu.2016.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/04/2016] [Accepted: 08/07/2016] [Indexed: 01/18/2023]
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31
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Marins FR, Limborço-Filho M, Xavier CH, Biancardi VC, Vaz GC, Stern JE, Oppenheimer SM, Fontes MAP. Functional topography of cardiovascular regulation along the rostrocaudal axis of the rat posterior insular cortex. Clin Exp Pharmacol Physiol 2016; 43:484-93. [DOI: 10.1111/1440-1681.12542] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 12/16/2015] [Accepted: 01/04/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Fernanda Ribeiro Marins
- Department of Physiology and Biophysics; INCT; Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte Brazil
| | - Marcelo Limborço-Filho
- Department of Physiology and Biophysics; INCT; Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte Brazil
| | - Carlos Henrique Xavier
- Department of Physiology and Biophysics; INCT; Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte Brazil
| | | | - Gisele C Vaz
- Department of Physiology and Biophysics; INCT; Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte Brazil
| | - Javier E. Stern
- Department of Physiology; Georgia Regents University; Augusta GA USA
| | - Stephen M Oppenheimer
- Department of Neurology; The Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Marco Antonio Peliky Fontes
- Department of Physiology and Biophysics; INCT; Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte Brazil
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Biancardi VC, Stranahan AM, Krause EG, de Kloet AD, Stern JE. Cross talk between AT1 receptors and Toll-like receptor 4 in microglia contributes to angiotensin II-derived ROS production in the hypothalamic paraventricular nucleus. Am J Physiol Heart Circ Physiol 2015; 310:H404-15. [PMID: 26637556 DOI: 10.1152/ajpheart.00247.2015] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 11/14/2015] [Indexed: 02/07/2023]
Abstract
ANG II is thought to increase sympathetic outflow by increasing oxidative stress and promoting local inflammation in the paraventricular nucleus (PVN) of the hypothalamus. However, the relative contributions of inflammation and oxidative stress to sympathetic drive remain poorly understood, and the underlying cellular and molecular targets have yet to be examined. ANG II has been shown to enhance Toll-like receptor (TLR)4-mediated signaling on microglia. Thus, in the present study, we aimed to determine whether ANG II-mediated activation of microglial TLR4 signaling is a key molecular target initiating local oxidative stress in the PVN. We found TLR4 and ANG II type 1 (AT1) receptor mRNA expression in hypothalamic microglia, providing molecular evidence for the potential interaction between these two receptors. In hypothalamic slices, ANG II induced microglial activation within the PVN (∼65% increase, P < 0.001), an effect that was blunted in the absence of functional TLR4. ANG II increased ROS production, as indicated by dihydroethidium fluorescence, within the PVN of rats and mice (P < 0.0001 in both cases), effects that were also dependent on the presence of functional TLR4. The microglial inhibitor minocycline attenuated ANG II-mediated ROS production, yet ANG II effects persisted in PVN single-minded 1-AT1a knockout mice, supporting the contribution of a non-neuronal source (likely microglia) to ANG II-driven ROS production in the PVN. Taken together, these results support functional interactions between AT1 receptors and TLR4 in mediating ANG II-dependent microglial activation and oxidative stress within the PVN. More broadly, our results support a functional interaction between the central renin-angiotensin system and innate immunity in the regulation of neurohumoral outflows from the PVN.
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Affiliation(s)
| | - Alexis M Stranahan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
| | - Eric G Krause
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Annette D de Kloet
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Javier E Stern
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
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Zhang M, Qin DN, Suo YP, Su Q, Li HB, Miao YW, Guo J, Feng ZP, Qi J, Gao HL, Mu JJ, Zhu GQ, Kang YM. Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates neurohormonal excitation in high salt-induced hypertension. Toxicol Lett 2015; 235:206-15. [PMID: 25891026 DOI: 10.1016/j.toxlet.2015.04.008] [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: 10/13/2014] [Revised: 04/11/2015] [Accepted: 04/13/2015] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) in the brain plays an important role in the progression of hypertension and hydrogen peroxide (H2O2) is a major component of ROS. The aim of this study is to explore whether endogenous H2O2 changed by polyethylene glycol-catalase (PEG-CAT) and aminotriazole (ATZ) in the hypothalamic paraventricular nucleus (PVN) regulates neurotransmitters, renin-angiotensin system (RAS), and cytokines, and whether subsequently affects the renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) in high salt-induced hypertension. Male Sprague-Dawley rats received a high-salt diet (HS, 8% NaCl) or a normal-salt diet (NS, 0.3% NaCl) for 10 weeks. Then rats were treated with bilateral PVN microinjection of PEG-CAT (0.2 i.u./50nl), an analog of endogenous catalase, the catalase inhibitor ATZ (10nmol/50nl) or vehicle. High salt-fed rats had significantly increased MAP, RSNA, plasma norepinephrine (NE) and pro-inflammatory cytokines (PICs). In addition, rats with high-salt diet had higher levels of NOX-2, NOX-4 (subunits of NAD(P)H oxidase), angiotensin-converting enzyme (ACE), interleukin-1beta (IL-1β), glutamate and NE, and lower levels of gamma-aminobutyric acid (GABA) and interleukin-10 (IL-10) in the PVN than normal diet rats. Bilateral PVN microinjection of PEG-CAT attenuated the levels of RAS and restored the balance of neurotransmitters and cytokines, while microinjection of ATZ into the PVN augmented those changes occurring in hypertensive rats. Our findings demonstrate that ROS component H2O2 in the PVN regulating MAP and RSNA are partly due to modulate neurotransmitters, renin-angiotensin system, and cytokines within the PVN in salt-induced hypertension.
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Affiliation(s)
- Meng Zhang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Da-Nian Qin
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Yu-Ping Suo
- Department of Obstetrics and Gynecology, Shanxi Provincial People's Hospital, Taiyuan 030012, China
| | - Qing Su
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Hong-Bao Li
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Yu-Wang Miao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jing Guo
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Zhi-Peng Feng
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jie Qi
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Hong-Li Gao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jian-Jun Mu
- Department of Cardiology, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an 710061, China
| | - Guo-Qing Zhu
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Department of Physiology, Nanjing Medical University, Nanjing 210029, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China.
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Reis WL, Yi CX, Gao Y, Tschöp MH, Stern JE. Brain innate immunity regulates hypothalamic arcuate neuronal activity and feeding behavior. Endocrinology 2015; 156:1303-15. [PMID: 25646713 PMCID: PMC4399317 DOI: 10.1210/en.2014-1849] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hypothalamic inflammation, involving microglia activation in the arcuate nucleus (ARC), is proposed as a novel underlying mechanism in obesity, insulin and leptin resistance. However, whether activated microglia affects ARC neuronal activity, and consequently basal and hormonal-induced food intake, is unknown. We show that lipopolysaccharide, an agonist of the toll-like receptor-4 (TLR4), which we found to be expressed in ARC microglia, inhibited the firing activity of the majority of orexigenic agouti gene-related protein/neuropeptide Y neurons, whereas it increased the activity of the majority of anorexigenic proopiomelanocortin neurons. Lipopolysaccharide effects in agouti gene-related protein/neuropeptide Y (but not in proopiomelanocortin) neurons were occluded by inhibiting microglia function or by blocking TLR4 receptors. Finally, we report that inhibition of hypothalamic microglia altered basal food intake, also preventing central orexigenic responses to ghrelin. Our studies support a major role for a TLR4-mediated microglia signaling pathway in the control of ARC neuronal activity and feeding behavior.
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Affiliation(s)
- Wagner L Reis
- Department of Physiology (W.L.R., J.E.S.), Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912; and Helmholtz Diabetes Center (C.-X.Y., Y.G., M.H.T.), Helmholtz Zentrum München and Technische Universität München, Munich 85764, Germany
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Lu J, Wen Y, Zhang L, Zhang C, Zhong W, Zhang L, Yu Y, Chen L, Xu D, Wang H. Prenatal ethanol exposure induces an intrauterine programming of enhanced sensitivity of the hypothalamic–pituitary–adrenal axis in female offspring rats fed with post-weaning high-fat diet. Toxicol Res (Camb) 2015. [DOI: 10.1039/c5tx00012b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
“Intrauterine programming” involved in the intrauterine origin of prenatal ethanol exposure induced enhanced sensitivity of the HPA axis in female offspring rats fed with high-fat diet.
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Affiliation(s)
- Juan Lu
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
- Department of Pharmacology
| | - Yinxian Wen
- Department of Orthopedic Surgery
- Zhongnan Hospital of Wuhan University
- Wuhan 430071
- China
| | - Li Zhang
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
| | - Chong Zhang
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
| | - Weihua Zhong
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
| | - Lu Zhang
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
| | - Ying Yu
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
| | - Liaobin Chen
- Department of Orthopedic Surgery
- Zhongnan Hospital of Wuhan University
- Wuhan 430071
- China
| | - Dan Xu
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease
| | - Hui Wang
- Department of Pharmacology
- Basic Medical School of Wuhan University
- Wuhan 430071
- China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease
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Sánchez-Pérez AM, Arnal-Vicente I, Santos FN, Pereira CW, ElMlili N, Sanjuan J, Ma S, Gundlach AL, Olucha-Bordonau FE. Septal projections to nucleus incertus in the rat: bidirectional pathways for modulation of hippocampal function. J Comp Neurol 2014; 523:565-88. [PMID: 25269409 DOI: 10.1002/cne.23687] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 09/26/2014] [Accepted: 09/26/2014] [Indexed: 11/10/2022]
Abstract
Projections from the nucleus incertus (NI) to the septum have been implicated in the modulation of hippocampal theta rhythm. In this study we describe a previously uncharacterized projection from the septum to the NI, which may provide feedback modulation of the ascending circuitry. Fluorogold injections into the NI resulted in retrograde labeling in the septum that was concentrated in the horizontal diagonal band and areas of the posterior septum including the septofimbrial and triangular septal nuclei. Double-immunofluorescent staining indicated that the majority of NI-projecting septal neurons were calretinin-positive and some were parvalbumin-, calbindin-, or glutamic acid decarboxylase (GAD)-67-positive. Choline acetyltransferase-positive neurons were Fluorogold-negative. Injection of anterograde tracers into medial septum, or triangular septal and septofimbrial nuclei, revealed fibers descending to the supramammillary nucleus, median raphe, and the NI. These anterogradely labeled varicosities displayed synaptophysin immunoreactivity, indicating septal inputs form synapses on NI neurons. Anterograde tracer also colocalized with GAD-67-positive puncta in labeled fibers, which in some cases made close synaptic contact with GAD-67-labeled NI neurons. These data provide evidence for the existence of an inhibitory descending projection from medial and posterior septum to the NI that provides a "feedback loop" to modulate the comparatively more dense ascending NI projections to medial septum and hippocampus. Neural processes and associated behaviors activated or modulated by changes in hippocampal theta rhythm may depend on reciprocal connections between ascending and descending pathways rather than on unidirectional regulation via the medial septum.
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Song XA, Jia LL, Cui W, Zhang M, Chen W, Yuan ZY, Guo J, Li HH, Zhu GQ, Liu H, Kang YM. Inhibition of TNF-α in hypothalamic paraventricular nucleus attenuates hypertension and cardiac hypertrophy by inhibiting neurohormonal excitation in spontaneously hypertensive rats. Toxicol Appl Pharmacol 2014; 281:101-8. [PMID: 25223692 DOI: 10.1016/j.taap.2014.09.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 08/20/2014] [Accepted: 09/04/2014] [Indexed: 02/07/2023]
Abstract
We hypothesized that chronic inhibition of tumor necrosis factor-alpha (TNF-α) in the hypothalamic paraventricular nucleus (PVN) delays the progression of hypertension and attenuates cardiac hypertrophy by up-regulating anti-inflammatory cytokines, reducing pro-inflammatory cytokines (PICs), decreasing nuclear factor-κB (NF-κB) p65 and NAD(P)H oxidase activities, as well as restoring the neurotransmitters balance in the PVN of spontaneously hypertensive rats (SHR). Adult normotensive Wistar-Kyoto (WKY) and SHR rats received bilateral PVN infusion of a TNF-α blocker (pentoxifylline or etanercept) or vehicle for 4weeks. SHR rats showed higher mean arterial pressure and cardiac hypertrophy compared with WKY rats, as indicated by increased whole heart weight/body weight ratio, whole heart weight/tibia length ratio, left ventricular weight/tibia length ratio, and cardiac atrial natriuretic peptide (ANP) and beta-myosin heavy chain (β-MHC) mRNA expressions. Compared with WKY rats, SHR rats had higher PVN levels of tyrosine hydroxylase, PICs, the chemokine monocyte chemoattractant protein-1 (MCP-1), NF-κB p65 activity, mRNA expressions of NOX-2 and NOX-4, and lower PVN levels of IL-10 and 67-kDa isoform of glutamate decarboxylase (GAD67), and higher plasma norepinephrine. PVN infusion of pentoxifylline or etanercept attenuated all these changes in SHR rats. These findings suggest that SHR rats have an imbalance between excitatory and inhibitory neurotransmitters, as well as an imbalance between pro- and anti-inflammatory cytokines in the PVN; and chronic inhibition of TNF-α in the PVN delays the progression of hypertension by restoring the balances of neurotransmitters and cytokines in the PVN, and attenuating PVN NF-κB p65 activity and oxidative stress, thereby attenuating hypertension-induced sympathetic hyperactivity and cardiac hypertrophy.
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Affiliation(s)
- Xin-Ai Song
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Lin-Lin Jia
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Wei Cui
- Department of Endocrinology and Metabolism, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Meng Zhang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Wensheng Chen
- Department of Cardiovascular Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Zu-Yi Yuan
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Jing Guo
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Hui-Hua Li
- Key Laboratory of Remodeling-related Cardiovascular Diseases, Department of Pathology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Guo-Qing Zhu
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Department of Physiology, Nanjing Medical University, Nanjing 210029, China
| | - Hao Liu
- Department of Neurosurgery, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an 710061, China.
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China.
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Dysfunctional astrocytic and synaptic regulation of hypothalamic glutamatergic transmission in a mouse model of early-life adversity: relevance to neurosteroids and programming of the stress response. J Neurosci 2014; 33:19534-54. [PMID: 24336719 DOI: 10.1523/jneurosci.1337-13.2013] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Adverse early-life experiences, such as poor maternal care, program an abnormal stress response that may involve an altered balance between excitatory and inhibitory signals. Here, we explored how early-life stress (ELS) affects excitatory and inhibitory transmission in corticotrophin-releasing factor (CRF)-expressing dorsal-medial (mpd) neurons of the neonatal mouse hypothalamus. We report that ELS associates with enhanced excitatory glutamatergic transmission that is manifested as an increased frequency of synaptic events and increased extrasynaptic conductance, with the latter associated with dysfunctional astrocytic regulation of glutamate levels. The neurosteroid 5α-pregnan-3α-ol-20-one (5α3α-THPROG) is an endogenous, positive modulator of GABAA receptors (GABAARs) that is abundant during brain development and rises rapidly during acute stress, thereby enhancing inhibition to curtail stress-induced activation of the hypothalamic-pituitary-adrenocortical axis. In control mpd neurons, 5α3α-THPROG potently suppressed neuronal discharge, but this action was greatly compromised by prior ELS exposure. This neurosteroid insensitivity did not primarily result from perturbations of GABAergic inhibition, but rather arose functionally from the increased excitatory drive onto mpd neurons. Previous reports indicated that mice (dams) lacking the GABAAR δ subunit (δ(0/0)) exhibit altered maternal behavior. Intriguingly, δ(0/0) offspring showed some hallmarks of abnormal maternal care that were further exacerbated by ELS. Moreover, in common with ELS, mpd neurons of δ(0/0) pups exhibited increased synaptic and extrasynaptic glutamatergic transmission and consequently a blunted neurosteroid suppression of neuronal firing. This study reveals that increased synaptic and tonic glutamatergic transmission may be a common maladaptation to ELS, leading to enhanced excitation of CRF-releasing neurons, and identifies neurosteroids as putative early regulators of the stress neurocircuitry.
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Cassaglia PA, Shi Z, Li B, Reis WL, Clute-Reinig NM, Stern JE, Brooks VL. Neuropeptide Y acts in the paraventricular nucleus to suppress sympathetic nerve activity and its baroreflex regulation. J Physiol 2014; 592:1655-75. [PMID: 24535439 DOI: 10.1113/jphysiol.2013.268763] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Neuropeptide Y (NPY), a brain neuromodulator that has been strongly implicated in the regulation of energy balance, also acts centrally to inhibit sympathetic nerve activity (SNA); however, the site and mechanism of action are unknown. In chloralose-anaesthetized female rats, nanoinjection of NPY into the paraventricular nucleus of the hypothalamus (PVN) dose-dependently suppressed lumbar SNA (LSNA) and its baroreflex regulation, and these effects were blocked by prior inhibition of NPY Y1 or Y5 receptors. Moreover, PVN injection of Y1 and Y5 receptor antagonists in otherwise untreated rats increased basal and baroreflex control of LSNA, indicating that endogenous NPY tonically inhibits PVN presympathetic neurons. The sympathoexcitation following blockade of PVN NPY inhibition was eliminated by prior PVN nanoinjection of the melanocortin 3/4 receptor inhibitor SHU9119. Moreover, presympathetic neurons, identified immunohistochemically using cholera toxin b neuronal tract tracing from the rostral ventrolateral medulla (RVLM), express NPY Y1 receptor immunoreactivity, and patch-clamp recordings revealed that both NPY and α-melanocyte-stimulating hormone (α-MSH) inhibit and stimulate, respectively, PVN-RVLM neurons. Collectively, these data suggest that PVN NPY inputs converge with α-MSH to influence presympathetic neurons. Together these results identify endogenous NPY as a novel and potent inhibitory neuromodulator within the PVN that may contribute to changes in SNA that occur in states associated with altered energy balance, such as obesity and pregnancy.
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Affiliation(s)
- Priscila A Cassaglia
- Oregon Health & Science University, Department of Physiology and Pharmacology, 1381 SW Sam Jackson Park Rd - L334, Portland, OR 97239, USA.
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40
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Affiliation(s)
- Susan Pyner
- School of Biological and Biomedical Sciences; Durham University; Durham UK
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41
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Biancardi VC, Son SJ, Ahmadi S, Filosa JA, Stern JE. Circulating angiotensin II gains access to the hypothalamus and brain stem during hypertension via breakdown of the blood-brain barrier. Hypertension 2013; 63:572-9. [PMID: 24343120 DOI: 10.1161/hypertensionaha.113.01743] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Angiotensin II-mediated vascular brain inflammation emerged as a novel pathophysiological mechanism in neurogenic hypertension. However, the precise underlying mechanisms and functional consequences in relation to blood-brain barrier (BBB) integrity and central angiotensin II actions mediating neurohumoral activation in hypertension are poorly understood. Here, we aimed to determine whether BBB permeability within critical hypothalamic and brain stem regions involved in neurohumoral regulation was altered during hypertension. Using digital imaging quantification after intravascularly injected fluorescent dyes and immunohistochemistry, we found increased BBB permeability, along with altered key BBB protein constituents, in spontaneously hypertensive rats within the hypothalamic paraventricular nucleus, the nucleus of the solitary tract, and the rostral ventrolateral medulla, all critical brain regions known to contribute to neurohumoral activation during hypertension. BBB disruption, including increased permeability and downregulation of constituent proteins, was prevented in spontaneously hypertensive rats treated with the AT1 receptor antagonist losartan, but not with hydralazine, a direct vasodilator. Importantly, we found circulating angiotensin II to extravasate into these brain regions, colocalizing with neurons and microglial cells. Taken together, our studies reveal a novel angiotensin II-mediated feed-forward mechanism during hypertension, by which circulating angiotensin II evokes increased BBB permeability, facilitating in turn its access to critical brain regions known to participate in blood pressure regulation.
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Perry JC, Bergamaschi CT, Campos RR, Silva AM, Tufik S. Interconnectivity of sympathetic and sleep networks is mediated through reduction of gamma aminobutyric acidergic inhibition in the paraventricular nucleus. J Sleep Res 2013; 23:168-75. [DOI: 10.1111/jsr.12110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 10/12/2013] [Indexed: 11/26/2022]
Affiliation(s)
- Juliana C. Perry
- Department of Psychobiology; Universidade Federal de São Paulo; São Paulo SP Brazil
| | | | - Ruy R. Campos
- Department of Physiology; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Adilson M. Silva
- Department of Physiology; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Sergio Tufik
- Department of Psychobiology; Universidade Federal de São Paulo; São Paulo SP Brazil
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43
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Rossi NF, Chen H, Maliszewska-Scislo M. Paraventricular nucleus control of blood pressure in two-kidney, one-clip rats: effects of exercise training and resting blood pressure. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1390-400. [PMID: 24089375 DOI: 10.1152/ajpregu.00546.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Exercise-induced changes in γ-aminobutyric acid (GABA) or nitric oxide signaling within the paraventricular nucleus (PVN) have not been studied in renovascular hypertension. We tested whether exercise training decreases mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in two-kidney, one-clip (2K-1C) hypertensive rats due to enhanced nitric oxide or GABA signaling within PVN. Conscious, unrestrained male Sprague-Dawley rats with either sham (Sham) or right renal artery clipping (2K-1C) were assigned to sedentary (SED) or voluntary wheel running (ExT) for 6 or 12 wk. MAP and angiotensin II (ANG II) were elevated in 2K-1C SED rats. The 2K-1C ExT rats displayed lower MAP at 6 wk that did not decline further by 12 wk. Plasma ANG II was lower in 2K-1C ExT rats. Increases in MAP, heart rate, and RSNA to blockade of PVN nitric oxide in 2K-1C SED rats were attenuated compared with either Sham group. Exercise training restored the responses in 2K-1C ExT rats. The increase in MAP in response to bicuculline was inversely correlated with baseline MAP. The rise in MAP was lower in 2K-1C SED vs. either Sham group and was normalized in the 2K-1C ExT rats. Paradoxically, heart rate and RSNA responses were not diminished in 2K-1C SED rats but were significantly lower in the 2K-1C ExT rats. Thus the decrease in arterial pressure in 2K-1C hypertension associated with exercise training is likely due to diminished excitatory inputs to PVN because of lower ANG II and higher nitritergic tone rather than enhanced GABA inhibition of sympathetic output.
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Affiliation(s)
- Noreen F Rossi
- John D. Dingell Veterans Affairs Medical Center, Departments of Internal Medicine and Physiology, Wayne State University School of Medicine, Detroit, Michigan
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44
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Son SJ, Filosa JA, Potapenko ES, Biancardi VC, Zheng H, Patel KP, Tobin VA, Ludwig M, Stern JE. Dendritic peptide release mediates interpopulation crosstalk between neurosecretory and preautonomic networks. Neuron 2013; 78:1036-49. [PMID: 23791197 DOI: 10.1016/j.neuron.2013.04.025] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2013] [Indexed: 01/08/2023]
Abstract
Although communication between neurons is considered a function of the synapse, neurons also release neurotransmitter from their dendrites. We found that dendritic transmitter release coordinates activity across distinct neuronal populations to generate integrative homeostatic responses. We show that activity-dependent vasopressin release from hypothalamic neuroendocrine neurons in the paraventricular nucleus stimulates neighboring (~100 μm soma-to-soma) presympathetic neurons, resulting in a sympathoexcitatory population response. This interpopulation crosstalk was engaged by an NMDA-mediated increase in dendritic Ca(2+), influenced by vasopressin's ability to diffuse in the extracellular space, and involved activation of CAN channels at the target neurons. Furthermore, we demonstrate that this interpopulation crosstalk plays a pivotal role in the generation of a systemic, polymodal neurohumoral response to a hyperosmotic challenge. Because dendritic release is emerging as a widespread process, our results suggest that a similar mechanism could mediate interpopulation crosstalk in other brain systems, particularly those involved in generating complex behaviors.
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Affiliation(s)
- Sook Jin Son
- Department of Physiology, Georgia Regents University, Augusta, GA 30912, USA
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45
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Saaltink DJ, Håvik B, Verissimo CS, Lucassen P, Vreugdenhil E. Doublecortin and doublecortin-like are expressed in overlapping and non-overlapping neuronal cell population: Implications for neurogenesis. J Comp Neurol 2012; 520:2805-23. [DOI: 10.1002/cne.23144] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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46
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Potapenko ES, Biancardi VC, Zhou Y, Stern JE. Altered astrocyte glutamate transporter regulation of hypothalamic neurosecretory neurons in heart failure rats. Am J Physiol Regul Integr Comp Physiol 2012; 303:R291-300. [PMID: 22696576 DOI: 10.1152/ajpregu.00056.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurohumoral activation, which includes augmented plasma levels of the neurohormone vasopressin (VP), is a common finding in heart failure (HF) that contributes to morbidity and mortality in this disease. While an increased activation of magnocellular neurosecretory cells (MNCs) and enhanced glutamate function in HF is well documented, the precise underlying mechanisms remain to be elucidated. Here, we combined electrophysiology and protein measurements to determine whether altered glial glutamate transporter function and/or expression occurs in the hypothalamic supraoptic nucleus (SON) during HF. Patch-clamp recordings obtained from MNCs in brain slices show that pharmacological blockade of astrocyte glutamate transporter 1 (GLT1) function [500 μM dihydrokainate (DHK)], resulted in a persistent N-methyl-D-aspartate receptor (NMDAR)-mediated inward current (tonic I(NMDA)) in sham rats, an effect that was significantly smaller in MNCs from HF rats. In addition, we found a diminished GLT1 protein content in plasma membrane (but not cytosolic) fractions of SON punches in HF rats. Conversely, astrocyte GLAST expression was significantly higher in the SON of HF rats, while nonselective blockade of glutamate transport activity (100 μM TBOA) evoked an enhanced tonic I(NMDA) activation in HF rats. Steady-state activation of NMDARs by extracellular glutamate levels was diminished during HF. Taken together, these results support a shift in the relative expression and function of two major glial glutamate transporters (from GLT1 to GLAST predominance) during HF. This shift may act as a compensatory mechanism to preserve an adequate basal glutamate uptake level in the face of an enhanced glutamatergic afferent activity in HF rats.
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Affiliation(s)
- Evgeniy S Potapenko
- Department of Physiology, Georgia Health Sciences University, Augusta, 30912, USA
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47
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Reis WL, Biancardi VC, Son S, Antunes-Rodrigues J, Stern JE. Enhanced expression of heme oxygenase-1 and carbon monoxide excitatory effects in oxytocin and vasopressin neurones during water deprivation. J Neuroendocrinol 2012; 24:653-63. [PMID: 22060896 PMCID: PMC3314108 DOI: 10.1111/j.1365-2826.2011.02249.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A growing body of evidence indiates that carbon monoxide (CO) acts as a gas neurotransmitter within the central nervous system. Although CO has been shown to affect neurohypophyseal hormone release in response to osmotic stimuli, the precise sources, targets and mechanisms underlying the actions of CO within the magnocellular neurosecretory system remain largely unknown. In the present study, we combined immunohistochemistry and patch-clamp electrophysiology to study the cellular distribution of the CO-synthase enzyme heme oxygenase type 1 (HO-1), as well as the actions of CO on oxytocin (OT) and vasopressin (VP) magnocellular neurosecretory cells (MNCs), in euhydrated (EU) and 48-h water-deprived rats (48WD). Our results show the expression of HO-1 immunoreactivity both in OT and VP neurones, as well as in a small proportion of astrocytes, both in supraoptic (SON) and paraventricular (PVN) nuclei. HO-1 expression, and its colocalisation with OT and VP neurones within the SON and PVN, was significantly enhanced in 48WD rats. Inhibition of HO activity with chromium mesoporphyrin IX chloride (CrMP; 20 μm) resulted in a slight membrane hyperpolarisation in SON neurones from EU rats, without significantly affecting their firing activity. In 48WD rats, on the other hand, CrMP resulted in a more robust membrane hyperpolarisation, significantly decreasing neuronal firing discharge. Taken together, our results indicate that magnocellular SON and PVN neurones express HO-1, and that CO acts as an excitatory gas neurotransmitter in this system. Moreover, we found that the expression and actions of CO were enhanced in water-deprived rats, suggesting that the state-dependent up-regulation of the HO-1/CO signalling pathway contributes to enhance MNCs firing activity during an osmotic challenge.
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Affiliation(s)
- W L Reis
- Department of Physiology, Georgia Health Sciences University, Augusta, GA 30912, USA
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48
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Farooqui AA, Farooqui T, Panza F, Frisardi V. Metabolic syndrome as a risk factor for neurological disorders. Cell Mol Life Sci 2012; 69:741-62. [PMID: 21997383 PMCID: PMC11115054 DOI: 10.1007/s00018-011-0840-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 09/08/2011] [Accepted: 09/15/2011] [Indexed: 02/07/2023]
Abstract
The metabolic syndrome is a cluster of common pathologies: abdominal obesity linked to an excess of visceral fat, insulin resistance, dyslipidemia and hypertension. At the molecular level, metabolic syndrome is accompanied not only by dysregulation in the expression of adipokines (cytokines and chemokines), but also by alterations in levels of leptin, a peptide hormone released by white adipose tissue. These changes modulate immune response and inflammation that lead to alterations in the hypothalamic 'bodyweight/appetite/satiety set point,' resulting in the initiation and development of metabolic syndrome. Metabolic syndrome is a risk factor for neurological disorders such as stroke, depression and Alzheimer's disease. The molecular mechanism underlying the mirror relationship between metabolic syndrome and neurological disorders is not fully understood. However, it is becoming increasingly evident that all cellular and biochemical alterations observed in metabolic syndrome like impairment of endothelial cell function, abnormality in essential fatty acid metabolism and alterations in lipid mediators along with abnormal insulin/leptin signaling may represent a pathological bridge between metabolic syndrome and neurological disorders such as stroke, Alzheimer's disease and depression. The purpose of this review is not only to describe the involvement of brain in the pathogenesis of metabolic syndrome, but also to link the pathogenesis of metabolic syndrome with neurochemical changes in stroke, Alzheimer's disease and depression to a wider audience of neuroscientists with the hope that this discussion will initiate more studies on the relationship between metabolic syndrome and neurological disorders.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH 43221, USA.
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Stern JE, Sonner PM, Son SJ, Silva FCP, Jackson K, Michelini LC. Exercise training normalizes an increased neuronal excitability of NTS-projecting neurons of the hypothalamic paraventricular nucleus in hypertensive rats. J Neurophysiol 2012; 107:2912-21. [PMID: 22357793 DOI: 10.1152/jn.00884.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elevated sympathetic outflow and altered autonomic reflexes, including impaired baroreflex function, are common findings observed in hypertensive disorders. Although a growing body of evidence supports a contribution of preautonomic neurons in the hypothalamic paraventricular nucleus (PVN) to altered autonomic control during hypertension, the precise underlying mechanisms remain unknown. Here, we aimed to determine whether the intrinsic excitability and repetitive firing properties of preautonomic PVN neurons that innervate the nucleus tractus solitarii (PVN-NTS neurons) were altered in spontaneously hypertensive rats (SHR). Moreover, given that exercise training is known to improve and/or correct autonomic deficits in hypertensive conditions, we evaluated whether exercise is an efficient behavioral approach to correct altered neuronal excitability in hypertensive rats. Patch-clamp recordings were obtained from retrogradely labeled PVN-NTS neurons in hypothalamic slices obtained from sedentary (S) and trained (T) Wistar-Kyoto (WKY) and SHR rats. Our results indicate an increased excitability of PVN-NTS neurons in SHR-S rats, reflected by an enhanced input-output function in response to depolarizing stimuli, a hyperpolarizing shift in Na(+) spike threshold, and smaller hyperpolarizing afterpotentials. Importantly, we found exercise training in SHR rats to restore all these parameters back to those levels observed in WKY-S rats. In several cases, exercise evoked opposing effects in WKY-S rats compared with SHR-S rats, suggesting that exercise effects on PVN-NTS neurons are state dependent. Taken together, our results suggest that elevated preautonomic PVN-NTS neuronal excitability may contribute to altered autonomic control in SHR rats and that exercise training efficiently corrects these abnormalities.
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Affiliation(s)
- Javier E Stern
- Dept. of Physiology, Georgia Health Sciences Univ., Augusta, GA 30912, USA.
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Filosa JA, Naskar K, Perfume G, Iddings JA, Biancardi VC, Vatta MS, Stern JE. Endothelin-mediated calcium responses in supraoptic nucleus astrocytes influence magnocellular neurosecretory firing activity. J Neuroendocrinol 2012; 24:378-92. [PMID: 22007724 DOI: 10.1111/j.1365-2826.2011.02243.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In addition to their peripheral vasoactive effects, accumulating evidence supports an important role for endothelins (ETs) in the regulation of the hypothalamic magnocellular neurosecretory system, which produces and releases the neurohormones vasopressin (VP) and oxytocin (OT). Still, the precise cellular substrates, loci and mechanisms underlying the actions of ETs on the magnocellular system are poorly understood. In the present study, we combined patch-clamp electrophysiology, confocal Ca(2+) imaging and immunohistochemistry to study the actions of ETs on supraoptic nucleus (SON) magnocellular neurosecretory neurones and astrocytes. Our studies show that ET-1 evoked rises in [Ca(2+) ](i) levels in SON astrocytes (but not neurones), an effect largely mediated by the activation of ET(B) receptors and mobilisation of thapsigargin-sensitive Ca(2+) stores. The presence of ET(B) receptors in SON astrocytes was also verified immunohistochemically. ET(B) receptor activation either increased (75%) or decreased (25%) SON firing activity, both in VP and putative OT neurones, and these effects were prevented when slices were preincubated in glutamate receptor blockers or nitric oxide synthase blockers, respectively. Moreover, ET(B) -mediated effects in SON neurones were also prevented by a gliotoxin compound, and when changes in [Ca(2+) ](i) were prevented with bath-applied BAPTA-AM or thapsigargin. Conversely, intracellular Ca(2+) chelation in the recorded SON neurones failed to block ET(B) -mediated effects. In summary, our results indicate that ET(B) receptor activation in SON astrocytes induces the mobilisation of [Ca(2+) ](i) , likely resulting in the activation of glutamate and nitric oxide signalling pathways, evoking in turn excitatory and inhibitory SON neuronal responses, respectively. Taken together, our study supports an important role for astrocytes in mediating the actions of ETs on the magnocellular neurosecretory system.
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Affiliation(s)
- J A Filosa
- Department of Physiology, Georgia Health Sciences University, Augusta, GA 30912, USA
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