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Kawada T, Yokoi A, Nishiura A, Kakuuchi M, Yokota S, Matsushita H, Li M, Uemura K, Saku K. Dynamic accentuated antagonism of heart rate control during different levels of vagal nerve stimulation intensity in rats. Am J Physiol Regul Integr Comp Physiol 2023; 324:R260-R270. [PMID: 36572552 DOI: 10.1152/ajpregu.00229.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Accentuated antagonism refers to a phenomenon in which the vagal effect on heart rate (HR) is augmented by background sympathetic tone. The dynamic aspect of accentuated antagonism remains to be elucidated during different levels of vagal nerve stimulation (VNS) intensity. We performed VNS on anesthetized rats (n = 8) according to a binary white noise signal with a switching interval of 500 ms at three different stimulation rates (low-intensity: 0-10 Hz, moderate-intensity: 0-20 Hz, and high-intensity: 0-40 Hz). The transfer function from VNS to HR was estimated with and without concomitant tonic sympathetic nerve stimulation (SNS) at 5 Hz. The asymptotic low-frequency (LF) gain (in beats/min/Hz) of the transfer function increased with SNS regardless of the VNS rate [low-intensity: 3.93 ± 0.70 vs. 5.82 ± 0.65 (P = 0.021), moderate-intensity: 3.87 ± 0.62 vs. 5.36 ± 0.53 (P = 0.018), high-intensity: 4.77 ± 0.85 vs. 7.39 ± 1.36 (P = 0.011)]. Moreover, SNS slightly increased the ratio of high-frequency (HF) gain to the LF gain. These effects of SNS were canceled by the pretreatment of ivabradine, an inhibitor of hyperpolarization-activated cyclic nucleotide-gated channels, in another group of rats (n = 6). Although background sympathetic tone antagonizes the vagal effect on mean HR, it enables finer HR control by increasing the dynamic gain of the vagal HR transfer function regardless of VNS intensity. When interpreting the HF component of HR variability, the augmenting effect from background sympathetic tone needs to be considered.
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Affiliation(s)
- Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Aimi Yokoi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Akitsugu Nishiura
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Midori Kakuuchi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Shohei Yokota
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Hiroki Matsushita
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Meihua Li
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Kazunori Uemura
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Keita Saku
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
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Translatome and Transcriptome Profiling of Hypoxic-Induced Rat Cardiomyocytes. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 22:1016-1024. [PMID: 33294289 PMCID: PMC7689039 DOI: 10.1016/j.omtn.2020.10.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 10/18/2020] [Indexed: 01/09/2023]
Abstract
Adult cardiac hypoxia as a crucial pathogenesis factor can induce detrimental effects on cardiac injury and dysfunction. The global transcriptome and translatome reflecting the cellular response to hypoxia have not yet been extensively studied in myocardium. In this study, we conducted RNA sequencing (RNA-seq) and ribosome profiling technique (polyribo-seq) in rat heart tissues and H9C2 cells exposed to different periods of hypoxia stress in vivo and in vitro. The temporal gene-expression profiling displayed the distinction of transcriptome and translatome, which were mainly concentrated in cell apoptosis, autophagy, DNA repair, angiogenesis, vascular process, and cardiac cell proliferation and differentiation. A large number of genes such as GNAI3, SEPT4, FANCL, BNIP3, TBX3, ESR2, PTGS2, KLF4, and ADRB2, whose transcript and translation levels are closely correlated, were identified to own a common RNA motif “5′-GAAGCUGCC-3′” in 5′ UTR. NCBP3 was further determined to recognize this RNA motif and facilitate translational process in myocardium under hypoxia stress. Taken together, our data show the close connection between alterations of transcriptome and translatome after hypoxia exposure, emphasizing the significance of translational regulation in related studies. The profiled molecular responses in current study may be valuable resources for advanced understanding of the mechanisms underlying hypoxia-induced effect on heart diseases.
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Vasquez EC, Aires R, Ton AMM, Amorim FG. New Insights on the Beneficial Effects of the Probiotic Kefir on Vascular Dysfunction in Cardiovascular and Neurodegenerative Diseases. Curr Pharm Des 2020; 26:3700-3710. [DOI: 10.2174/1381612826666200304145224] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/26/2020] [Indexed: 12/14/2022]
Abstract
The mechanisms responsible for cardiovascular and neurodegenerative diseases have been the focus of
experimental and clinical studies for decades. The relationship between the gut microbiota and the organs and
system tissues represents the research field that has generated the highest number of publications. Homeostasis of
the gut microbiota is important to the host because it promotes maturation of the autoimmune system, harmonic
integrative functions of the brain, and the normal function of organs related to cardiovascular and metabolic systems.
On the other hand, when a gut microbiota dysbiosis occurs, the target organs become vulnerable to the
onset or aggravation of complex chronic conditions, such as cardiovascular (e.g., arterial hypertension) and neurodegenerative
(e.g., dementia) diseases. In the present brief review, we discuss the main mechanisms involved in
those disturbances and the promising beneficial effects that have been revealed using functional food (nutraceuticals),
such as the traditional probiotic Kefir. Here, we highlight the current scientific advances, concerns, and
limitations about the use of this nutraceutical. The focus of our discussion is the endothelial dysfunction that
accompanies hypertension and the neurovascular dysfunction that characterizes ageing-related dementia in patients
suffering from Alzheimer's disease.
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Affiliation(s)
- Elisardo C. Vasquez
- Pharmaceutical Sciences Graduate Program, Vila Velha University (UVV), Vila Velha, ES, Brazil
| | - Rafaela Aires
- Physiological Sciences Graduate Program, Federal University of Espirito Santo (UFES), Vitoria, ES, Brazil
| | - Alyne M. M. Ton
- Pharmaceutical Sciences Graduate Program, Vila Velha University (UVV), Vila Velha, ES, Brazil
| | - Fernanda G. Amorim
- Pharmaceutical Sciences Graduate Program, Vila Velha University (UVV), Vila Velha, ES, Brazil
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Kim LJ, Polotsky VY. Carotid Body and Metabolic Syndrome: Mechanisms and Potential Therapeutic Targets. Int J Mol Sci 2020; 21:E5117. [PMID: 32698380 PMCID: PMC7404212 DOI: 10.3390/ijms21145117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/11/2020] [Accepted: 07/16/2020] [Indexed: 12/19/2022] Open
Abstract
The carotid body (CB) is responsible for the peripheral chemoreflex by sensing blood gases and pH. The CB also appears to act as a peripheral sensor of metabolites and hormones, regulating the metabolism. CB malfunction induces aberrant chemosensory responses that culminate in the tonic overactivation of the sympathetic nervous system. The sympatho-excitation evoked by CB may contribute to the pathogenesis of metabolic syndrome, inducing systemic hypertension, insulin resistance and sleep-disordered breathing. Several molecular pathways are involved in the modulation of CB activity, and their pharmacological manipulation may lead to overall benefits for cardiometabolic diseases. In this review, we will discuss the role of the CB in the regulation of metabolism and in the pathogenesis of the metabolic dysfunction induced by CB overactivity. We will also explore the potential pharmacological targets in the CB for the treatment of metabolic syndrome.
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Affiliation(s)
- Lenise J. Kim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA;
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Souza PRMD, da Palma RK, Vieira RP, Santos FD, Monteiro-De-Moraes WMA, Medeiros A, Koike MK, Arantes-Costa FM, De Angelis K, Irigoyen MC, Consolim Colombo FM. Early activation of ubiquitin-proteasome system at the diaphragm tissue occurs independently of left ventricular dysfunction in SHR rats. Exp Biol Med (Maywood) 2020; 245:245-253. [PMID: 31986909 DOI: 10.1177/1535370219897883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Hypertensive status induces modifications in the respiratory profile. Previous studies have indicated that hypertensive rats show increased respiratory-sympathetic coupling compared to normotensive rats. However, these effects and especially the mechanisms underlying such effects are not well known. Thus, we evaluated the influence of high blood pressure and autonomic dysfunction on a ventilatory pattern associated with lung injury and on the ubiquitin-proteasome system of the diaphragm muscle. Autonomic cardiovascular modulation (systolic BP variance and low-frequency band and pulse interval variance) and arterial blood gases patterns (pH, pO2, HCO3, SpO2), can be changed by hypertension, as well exacerbated chemoreflex pressor response. We observed that the diaphragm muscle of SHR showed increase in type I cross-sectional fiber (16%) and reduction in type II cross-sectional fiber area (41%), increased activity of the ubiquitin-proteasome system and lipid peroxidation, with no differences between groups in the analysis of ubiquitinated proteins and misfolded proteins. Our results showed that hypertension induced functional compensatory/adverse alterations associated with diaphragm fiber type changes and protein degradation as well as changed autonomic control of circulation. In conclusion, we believe there is an adaptation in ventilatory pattern in regarding to prevent the development of fatigue and muscle weakness and improve ventilatory endurance. Impact statement It was well known that hypertension can be driven by increased sympathetic activity and has been documented as a central link between autonomic dysfunction and alterations in the respiratory pattern. Our study demonstrated the impact of hypertension in ventilatory mechanics and their relationship with diaphragm muscle protein degradation. These findings may assist us in future alternative treatments to prevent diaphragm fatigue and weakness in hypertensive patients.
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Affiliation(s)
- Pamella Ramona Moraes de Souza
- Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo (FMUSP), Avenida Dr Eneas de Carvalho Aguiar 44, São Paulo/SP, Brazil 05403-000.,Department of Post-graduation in Medicine, Nove de Julho University (UNINOVE), Rua Vergueiro 235/249, São Paulo/SP, Brazil 01504-001
| | - Renata Kelly da Palma
- Department of Post-graduation in Medicine, Nove de Julho University (UNINOVE), Rua Vergueiro 235/249, São Paulo/SP, Brazil 01504-001.,Institute for Bioengineering of Catalonia, Biomimetic systems for cell engineering. Barcelona, Spain (IBEC). C. Baldiri Reixac, 15-21 Barcelona. 08028
| | - Rodolfo Paula Vieira
- Department of Post-graduation in Medicine, Nove de Julho University (UNINOVE), Rua Vergueiro 235/249, São Paulo/SP, Brazil 01504-001.,Institute for Bioengineering of Catalonia, Biomimetic systems for cell engineering. Barcelona, Spain (IBEC). C. Baldiri Reixac, 15-21 Barcelona. 08028
| | - Fernando Dos Santos
- Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo (FMUSP), Avenida Dr Eneas de Carvalho Aguiar 44, São Paulo/SP, Brazil 05403-000
| | - Wilson Max Almeida Monteiro-De-Moraes
- Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo (FMUSP), Avenida Dr Eneas de Carvalho Aguiar 44, São Paulo/SP, Brazil 05403-000
| | | | - Marcia Kiyomi Koike
- Department of Medicine, Center of Development of Medical Education, CEDEM, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Fernanda Magalhães Arantes-Costa
- Department of Medicine, Center of Development of Medical Education, CEDEM, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Kátia De Angelis
- Federal University of Sao Paulo.Rua Pedro de Toledo, 1800. São Paulo/SP, Brazil 04021-001
| | - Maria Claudia Irigoyen
- Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo (FMUSP), Avenida Dr Eneas de Carvalho Aguiar 44, São Paulo/SP, Brazil 05403-000
| | - Fernanda Marciano Consolim Colombo
- Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo (FMUSP), Avenida Dr Eneas de Carvalho Aguiar 44, São Paulo/SP, Brazil 05403-000.,Department of Post-graduation in Medicine, Nove de Julho University (UNINOVE), Rua Vergueiro 235/249, São Paulo/SP, Brazil 01504-001
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Zubcevic J, Watkins J, Perez PD, Colon-Perez LM, Long MT, Febo M, Hayward L. MEMRI reveals altered activity in brain regions associated with anxiety, locomotion, and cardiovascular reactivity on the elevated plus maze in the WKY vs SHR rats. Brain Imaging Behav 2019; 12:1318-1331. [PMID: 29181695 DOI: 10.1007/s11682-017-9798-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Individuals with anxiety/depression often have exaggerated cardiovascular responses to stressful stimuli and a comorbidity with hypertension. Alternatively, individuals with hypertension can be more anxious. In the present study cardiovascular changes were evaluated during behavioral testing of anxious behavior on the elevated plus maze (EPM) in the spontaneously hypertensive rat (SHR), a rodent model of neurogenic hypertension, and compared to the response of the more anxious, but normotensive, Wistar-Kyoto rat (WKY). Manganese-enhanced magnetic resonance imaging (MEMRI) was used to identify regional differences in baseline brain activity. Parallel to indicators of elevated behavioral anxiety on the EPM, WKYs had a greater increase in blood pressure but not heart rate when compared to the SHR while on the EPM. Associated with differences in anxiety-related behavior and autonomic responses, we observed increased baseline activity in the amygdala, central gray, habenula and interpeduncular nucleus with MEMRI of the WKY compared to the SHR. Conversely, elevated baseline brain activity was found in regions associated with blood pressure control and system arousal, including the hypothalamus, locus coeruleus and pedunculopontine tegmental nucleus, in the SHR vs WKY, in-line with increased resting blood pressure and increased mobility in this strain. Lastly, reduced activity in hippocampal regions was identified in the SHR compared to the WKY and may be associated with cognitive impairment previously reported in the SHR. Thus, autonomic reactivity may be a true measure of stress in rodent models of anxiety and MEMRI presents a powerful technique to uncover novel brain mechanisms of blood pressure control.
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Affiliation(s)
- Jasenka Zubcevic
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr., BSB 3-32, Gainesville, FL, 32610-0144, USA
| | - Jacqueline Watkins
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr., BSB 3-32, Gainesville, FL, 32610-0144, USA
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, 32610-0256, USA
| | - Luis M Colon-Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, 32610-0256, USA
| | - Maureen T Long
- Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610-0123, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, 32610-0256, USA
| | - Linda Hayward
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr., BSB 3-32, Gainesville, FL, 32610-0144, USA.
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7
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Coblentz PD, Ahn B, Hayward LF, Yoo JK, Christou DD, Ferreira LF. Small-hairpin RNA and pharmacological targeting of neutral sphingomyelinase prevent diaphragm weakness in rats with heart failure and reduced ejection fraction. Am J Physiol Lung Cell Mol Physiol 2019; 316:L679-L690. [PMID: 30702345 DOI: 10.1152/ajplung.00516.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Heart failure with reduced ejection fraction (HFREF) increases neutral sphingomyelinase (NSMase) activity and mitochondrial reactive oxygen species (ROS) emission and causes diaphragm weakness. We tested whether a systemic pharmacological NSMase inhibitor or short-hairpin RNA (shRNA) targeting NSMase isoform 3 (NSMase3) would prevent diaphragm abnormalities induced by HFREF caused by myocardial infarction. In the pharmacological intervention, we used intraperitoneal injection of GW4869 or vehicle. In the genetic intervention, we injected adeno-associated virus serotype 9 (AAV9) containing shRNA targeting NSMase3 or a scrambled sequence directly into the diaphragm. We also studied acid sphingomyelinase-knockout mice. GW4869 prevented the increase in diaphragm ceramide content, weakness, and tachypnea caused by HFREF. For example, maximal specific forces (in N/cm2) were vehicle [sham 31 ± 2 and HFREF 26 ± 2 ( P < 0.05)] and GW4869 (sham 31 ± 2 and HFREF 31 ± 1). Respiratory rates were (in breaths/min) vehicle [sham 61 ± 3 and HFREF 84 ± 11 ( P < 0.05)] and GW4869 (sham 66 ± 2 and HFREF 72 ± 2). AAV9-NSMase3 shRNA prevented heightening of diaphragm mitochondrial ROS and weakness [in N/cm2, AAV9-scrambled shRNA: sham 31 ± 2 and HFREF 27 ± 2 ( P < 0.05); AAV9-NSMase3 shRNA: sham 30 ± 1 and HFREF 30 ± 1] but displayed tachypnea. Both wild-type and ASMase-knockout mice with HFREF displayed diaphragm weakness. Our study suggests that activation of NSMase3 causes diaphragm weakness in HFREF, presumably through accumulation of ceramide and elevation in mitochondrial ROS. Our data also reveal a novel inhibitory effect of GW4869 on tachypnea in HFREF likely mediated by changes in neural control of breathing.
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Affiliation(s)
- Philip D Coblentz
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida , Gainesville, Florida
| | - Bumsoo Ahn
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida , Gainesville, Florida
| | - Linda F Hayward
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida , Gainesville, Florida
| | - Jeung-Ki Yoo
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida , Gainesville, Florida
| | - Demetra D Christou
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida , Gainesville, Florida
| | - Leonardo F Ferreira
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida , Gainesville, Florida
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8
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Abstract
The discovery of carotid bodies as sensory receptors for detecting arterial blood oxygen levels, and the identification and elucidation of the roles of hypoxia-inducible factors (HIFs) in oxygen homeostasis have propelled the field of oxygen biology. This review highlights the gas-messenger signaling mechanisms associated with oxygen sensing, as well as transcriptional and non-transcriptional mechanisms underlying the maintenance of oxygen homeostasis by HIFs and their relevance to physiology and pathology.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, Illinois;
| | - Gregg L Semenza
- Departments of Pediatrics, Medicine, Oncology, Radiation Oncology, and Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland; and McKusick-Nathans Institute of Genetic Medicine and Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Klippel BF, Duemke LB, Leal MA, Friques AGF, Dantas EM, Dalvi RF, Gava AL, Pereira TMC, Andrade TU, Meyrelles SS, Campagnaro BP, Vasquez EC. Effects of Kefir on the Cardiac Autonomic Tones and Baroreflex Sensitivity in Spontaneously Hypertensive Rats. Front Physiol 2016; 7:211. [PMID: 27375490 PMCID: PMC4895057 DOI: 10.3389/fphys.2016.00211] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/22/2016] [Indexed: 11/21/2022] Open
Abstract
Aims: It has been previously shown that the probiotic kefir (a symbiotic matrix containing acid bacteria and yeasts) attenuated the hypertension and the endothelial dysfunction in spontaneously hypertensive rats (SHR). In the present study, the effect of chronic administration of kefir on the cardiac autonomic control of heart rate (HR) and baroreflex sensitivity (BRS) in SHR was evaluated. Methods: SHR were treated with kefir (0.3 mL/100 g body weight) for 60 days and compared with non-treated SHR and with normotensive Wistar-Kyoto rats. Cardiac autonomic vagal (VT) and sympathetic (ST) tones were estimated through the blockade of the cardiac muscarinic receptors (methylatropine) and the blockade of β1−adrenoceptor (atenolol). The BRS was evaluated by the tachycardia and bradycardia responses to vasoactive drug-induced decreases and increases in arterial blood pressure (BP), respectively. Additionally, spontaneous BRS was estimated by autoregressive spectral analysis. Results: Kefir-treated SHR exhibited significant attenuation of basal BP, HR, and cardiac hypertrophy compared to non-treated SHR (12, 13, and 21%, respectively). Cardiac VT and ST were significantly altered in the SHR (~40 and ~90 bpm) compared with Wistar rats (~120 and ~30 bpm) and were partially recovered in SHR-kefir (~90 and ~25 bpm). SHR exhibited an impaired bradycardic BRS (~50%) compared with Wistar rats, which was reduced to ~40% in the kefir-treated SHR and abolished by methylatropine in all groups. SHR also exhibited a significant impairment of the tachycardic BRS (~23%) compared with Wistar rats and this difference was reduced to 8% in the SHR-kefir. Under the action of atenolol the residual reflex tachycardia was smaller in SHR than in Wistar rats and kefir attenuated this abnormality. Spectral analysis revealed increased low frequency components of BP (~3.5-fold) and pulse interval (~2-fold) compared with Wistar rats and these differences were reduced by kefir-treatment to ~1.6- and ~1.5-fold, respectively. Spectral analysis also showed an impairment of spontaneous BRS in SHR, but kefir-treatment caused only a tendency to reverse this result. Conclusions: The novelty of this study is that daily chronic consumption of a low dose of kefir reduced the impairment of the cardiac autonomic control of HR and of the impaired BRS in SHR.
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Affiliation(s)
- Brunella F Klippel
- Laboratory of Translational Physiology, Federal University of Espirito Santo Vitoria, Brazil
| | - Licia B Duemke
- Pharmaceutical Sciences Graduate Program, Vila Velha University Vila Velha, Brazil
| | - Marcos A Leal
- Laboratory of Translational Physiology, Federal University of Espirito Santo Vitoria, Brazil
| | - Andreia G F Friques
- Pharmaceutical Sciences Graduate Program, Vila Velha University Vila Velha, Brazil
| | - Eduardo M Dantas
- Department of Physiology, Federal University of Vale Sao Francisco Petrolina, Brazil
| | - Rodolfo F Dalvi
- Department of Biochemistry, Institute of Education, Science and Technology Vila Velha, Brazil
| | - Agata L Gava
- Laboratory of Translational Physiology, Federal University of Espirito Santo Vitoria, Brazil
| | - Thiago M C Pereira
- Pharmaceutical Sciences Graduate Program, Vila Velha UniversityVila Velha, Brazil; Department of Biochemistry, Institute of Education, Science and TechnologyVila Velha, Brazil
| | - Tadeu U Andrade
- Pharmaceutical Sciences Graduate Program, Vila Velha University Vila Velha, Brazil
| | - Silvana S Meyrelles
- Laboratory of Translational Physiology, Federal University of Espirito Santo Vitoria, Brazil
| | - Bianca P Campagnaro
- Pharmaceutical Sciences Graduate Program, Vila Velha University Vila Velha, Brazil
| | - Elisardo C Vasquez
- Laboratory of Translational Physiology, Federal University of Espirito SantoVitoria, Brazil; Pharmaceutical Sciences Graduate Program, Vila Velha UniversityVila Velha, Brazil
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Gutkowska J, Aliou Y, Lavoie JL, Gaab K, Jankowski M, Broderick TL. Oxytocin decreases diurnal and nocturnal arterial blood pressure in the conscious unrestrained spontaneously hypertensive rat. ACTA ACUST UNITED AC 2016; 23:111-21. [PMID: 27020751 DOI: 10.1016/j.pathophys.2016.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 01/27/2023]
Abstract
In this study, we assessed the effects of oxytocin (OT) on mean arterial blood pressure (MAP), heart rate (HR), and locomotor activity (LA) in male spontaneous hypertensive rats (SHR) and Sprague-Dawley (SDR) controls using telemetry. OT was given by intravenous injections of 0.1, 0.2 or 0.4mg/kg to assess short term acute effects or by daily subcutaneous injections of 0.5 or 1.0mg/kg for 5 days. Compared to the saline infusion, (i) intravenous OT, regardless of concentration, increased MAP in SHR and SDR, (ii) HR increased, but was periodically lower in both strains with 0.2 or 0.4mg/kg, and (iii) no effects of OT on LA were observed. Subcutaneous injections demonstrated that (i) 1.0mg/kg for 5days lowered diurnal MAP and HR in SDR and SHR, persisting for 6 days, (ii) 1.0mg/kg decreased nocturnal HR in SDR, (iii) 0.5 and 1.0mg/kg decreased MAP with minor effects on HR in the SHR, and lastly (iv) OT decreased LA mainly during the diurnal cycle in both strains. Our main results show that OT induces significant beneficial effects on cardiovascular function over several diurnal and nocturnal cycles in the SHR, with the most prominent effect being a robust decrease in MAP.
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Affiliation(s)
- Jolanta Gutkowska
- Cardiovascular Biochemistry Laboratory, Centre de Recherché du Centre Hospitalier de l 'Université de Montréal, Montréal, Québec, Canada; Département de Medecine, Université de Montréal, Montreal, Quebec, Canada
| | - Yessoufou Aliou
- Cardiovascular Biochemistry Laboratory, Centre de Recherché du Centre Hospitalier de l 'Université de Montréal, Montréal, Québec, Canada; Département de Pharmacologie, Université de Montréal, Montreal, Quebec, Canada
| | - Julie L Lavoie
- Cardiovascular Biochemistry Laboratory, Centre de Recherché du Centre Hospitalier de l 'Université de Montréal, Montréal, Québec, Canada; Department de Kinesiologie, Université de Montréal, Montreal, Quebec, Canada
| | - Katie Gaab
- Department of Physiology, Laboratory of Diabetes and Exercise Metabolism, Midwestern University, Glendale, AZ, USA
| | - Marek Jankowski
- Cardiovascular Biochemistry Laboratory, Centre de Recherché du Centre Hospitalier de l 'Université de Montréal, Montréal, Québec, Canada; Département de Medecine, Université de Montréal, Montreal, Quebec, Canada
| | - Tom L Broderick
- Department of Physiology, Laboratory of Diabetes and Exercise Metabolism, Midwestern University, Glendale, AZ, USA.
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Interaction of Hydrogen Sulfide with Oxygen Sensing under Hypoxia. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:758678. [PMID: 26078818 PMCID: PMC4442289 DOI: 10.1155/2015/758678] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 01/22/2015] [Indexed: 01/18/2023]
Abstract
Based on the discovery of endogenous H2S production, many in depth studies show this gasotransmitter with a variety of physiological and pathological functions. Three enzymes, cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (MST), are involved in enzymatic production of H2S. Emerging evidence has elucidated an important protective role of H2S in hypoxic conditions in many mammalian systems. However, the mechanisms by which H2S senses and responses to hypoxia are largely elusive. Hypoxia-inducible factors (HIFs) function as key regulators of oxygen sensing, activating target genes expression under hypoxia. Recent studies have shown that exogenous H2S regulates HIF action in different patterns. The activation of carotid bodies is a sensitive and prompt response to hypoxia, rapidly enhancing general O2 supply. H2S has been identified as an excitatory mediator of hypoxic sensing in the carotid bodies. This paper presents a brief review of the roles of these two pathways which contribute to hypoxic sensing of H2S.
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Prabhakhar NR, Joyner MJ. Tasting arterial blood: what do the carotid chemoreceptors sense? Front Physiol 2015; 5:524. [PMID: 25642193 PMCID: PMC4294136 DOI: 10.3389/fphys.2014.00524] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/20/2014] [Indexed: 01/16/2023] Open
Abstract
The carotid bodies are sensory organs that detect the chemical composition of the arterial blood. The carotid body sensory activity increases in response to arterial hypoxemia and the ensuing chemoreflex regulates vital homeostatic functions. Recent studies suggest that the carotid bodies might also sense arterial blood glucose and circulating insulin levels. This review focuses on how the carotid bodies sense O2, glucose, and insulin and some potential implications of these sensory functions on physiological regulation and in pathophysiological conditions. Emerging evidence suggests that carbon monoxide (CO)-regulated hydrogen sulfide (H2S), stemming from hypoxia, depolarizes type I cells by inhibiting certain K+ channels, facilitates voltage-gated Ca2+ influx leading to sensory excitation of the carotid body. Elevated CO and decreased H2S renders the carotid bodies insensitive to hypoxia resulting in attenuated ventilatory adaptations to high altitude hypoxia, whereas reduced CO and high H2S result in hypersensitivity of the carotid bodies to hypoxia and hypertension. Acute hypoglycemia augments the carotid body responses to hypoxia but that a prolonged lack of glucose in the carotid bodies can lead to a failure to sense hypoxia. Emerging evidence also indicates that carotid bodies might sense insulin directly independent of its effect on glucose, linking the carotid bodies to the pathophysiological consequences of the metabolic syndrome. How glucose and insulin interact with the CO-H2S signaling is an area of ongoing study.
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Affiliation(s)
- Nanduri R Prabhakhar
- Institute for Integrative Physiology, Center for Systems Biology of O2 Sensing, The University of Chicago Chicago, IL, USA
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Hernandez ME, Hayward LF. Effect of DOCA/salt hypertension on CRF expression in the amygdala and the autonomic stress response in conscious rats. Auton Neurosci 2014; 185:83-92. [DOI: 10.1016/j.autneu.2014.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 12/26/2022]
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Wu KLH, Hung CY, Chan JYH, Wu CW. An increase in adenosine-5'-triphosphate (ATP) content in rostral ventrolateral medulla is engaged in the high fructose diet-induced hypertension. J Biomed Sci 2014; 21:8. [PMID: 24467657 PMCID: PMC3913325 DOI: 10.1186/1423-0127-21-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/20/2014] [Indexed: 12/21/2022] Open
Abstract
Background The increase in fructose ingestion has been linked to overdrive of sympathetic activity and hypertension associated with the metabolic syndrome. The premotor neurons for generation of sympathetic vasomotor activity reside in the rostral ventrolateral medulla (RVLM). Activation of RVLM results in sympathoexcitation and hypertension. Neurons in the central nervous system are able to utilize fructose as a carbon source of ATP production. We examined in this study whether fructose affects ATP content in RVLM and its significance in the increase in central sympathetic outflow and hypertension induced by the high fructose diet (HFD). Results In normotensive rats fed with high fructose diet (HFD) for 12 weeks, there was a significant increase in tissue ATP content in RVLM, accompanied by the increases in the sympathetic vasomotor activity and blood pressure. These changes were blunted by intracisternal infusion of an ATP synthase inhibitor, oligomycin, to the HFD-fed animals. In the catecholaminergic-containing N2a cells, fructose dose-dependently upregulated the expressions of glucose transporter 2 and 5 (GluT2, 5) and the rate-limiting enzyme of fructolysis, ketohexokinase (KHK), leading to the increases in pyruvate and ATP production, as well as the release of the neurotransmitter, dopamine. These cellular events were significantly prevented after the gene knocking down by lentiviral transfection of small hairpin RNA against KHK. Conclusion These results suggest that increases in ATP content in RVLM may be engaged in the augmented sympathetic vasomotor activity and hypertension associated with the metabolic syndrome induced by the HFD. At cellular level, the increase in pyruvate levels via fructolysis is involved in the fructose-induced ATP production and the release of neurotransmitter.
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Affiliation(s)
- Kay L H Wu
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung 83301, Taiwan.
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Angheben JMM, Schoorlemmer GHM, Rossi MV, Silva TA, Cravo SL. Cardiovascular responses induced by obstructive apnea are enhanced in hypertensive rats due to enhanced chemoreceptor responsivity. PLoS One 2014; 9:e86868. [PMID: 24466272 PMCID: PMC3900660 DOI: 10.1371/journal.pone.0086868] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 12/17/2013] [Indexed: 11/17/2022] Open
Abstract
Spontaneously hypertensive rats (SHR), like patients with sleep apnea, have hypertension, increased sympathetic activity, and increased chemoreceptor drive. We investigated the role of carotid chemoreceptors in cardiovascular responses induced by obstructive apnea in awake SHR. A tracheal balloon and vascular cannulas were implanted, and a week later, apneas of 15 s each were induced. The effects of apnea were more pronounced in SHR than in control rats (Wistar Kyoto; WKY). Blood pressure increased by 57±3 mmHg during apnea in SHR and by 28±3 mmHg in WKY (p<0.05, n = 14/13). The respiratory effort increased by 53±6 mmHg in SHR and by 34±5 mmHg in WKY. The heart rate fell by 209±19 bpm in SHR and by 155±16 bpm in WKY. The carotid chemoreceptors were then inactivated by the ligation of the carotid body artery, and apneas were induced two days later. The inactivation of chemoreceptors reduced the responses to apnea and abolished the difference between SHR and controls. The apnea-induced hypertension was 11±4 mmHg in SHR and 8±4 mmHg in WKY. The respiratory effort was 15±2 mmHg in SHR and 15±2 mmHg in WKY. The heart rate fell 63±18 bpm in SHR and 52±14 bpm in WKY. Similarly, when the chemoreceptors were unloaded by the administration of 100% oxygen, the responses to apnea were reduced. In conclusion, arterial chemoreceptors contribute to the responses induced by apnea in both strains, but they are more important in SHR and account for the exaggerated responses of this strain to apnea.
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Affiliation(s)
- Juliana M M Angheben
- Department of Physiology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil
| | - Guus H M Schoorlemmer
- Department of Physiology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil
| | - Marcio V Rossi
- Department of Physiology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil
| | - Thiago A Silva
- Department of Physiology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil
| | - Sergio L Cravo
- Department of Physiology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil
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Inherent variations in CO-H2S-mediated carotid body O2 sensing mediate hypertension and pulmonary edema. Proc Natl Acad Sci U S A 2014; 111:1174-9. [PMID: 24395806 DOI: 10.1073/pnas.1322172111] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxygen (O2) sensing by the carotid body and its chemosensory reflex is critical for homeostatic regulation of breathing and blood pressure. Humans and animals exhibit substantial interindividual variation in this chemosensory reflex response, with profound effects on cardiorespiratory functions. However, the underlying mechanisms are not known. Here, we report that inherent variations in carotid body O2 sensing by carbon monoxide (CO)-sensitive hydrogen sulfide (H2S) signaling contribute to reflex variation in three genetically distinct rat strains. Compared with Sprague-Dawley (SD) rats, Brown-Norway (BN) rats exhibit impaired carotid body O2 sensing and develop pulmonary edema as a consequence of poor ventilatory adaptation to hypobaric hypoxia. Spontaneous Hypertensive (SH) rat carotid bodies display inherent hypersensitivity to hypoxia and develop hypertension. BN rat carotid bodies have naturally higher CO and lower H2S levels than SD rat, whereas SH carotid bodies have reduced CO and greater H2S generation. Higher CO levels in BN rats were associated with higher substrate affinity of the enzyme heme oxygenase 2, whereas SH rats present lower substrate affinity and, thus, reduced CO generation. Reducing CO levels in BN rat carotid bodies increased H2S generation, restoring O2 sensing and preventing hypoxia-induced pulmonary edema. Increasing CO levels in SH carotid bodies reduced H2S generation, preventing hypersensitivity to hypoxia and controlling hypertension in SH rats.
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