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Ang R, Marina N. Low-Frequency Oscillations in Cardiac Sympathetic Neuronal Activity. Front Physiol 2020; 11:236. [PMID: 32256390 PMCID: PMC7093552 DOI: 10.3389/fphys.2020.00236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/02/2020] [Indexed: 12/25/2022] Open
Abstract
Sudden cardiac death caused by ventricular arrhythmias is among the leading causes of mortality, with approximately half of all deaths attributed to heart disease worldwide. Periodic repolarization dynamics (PRD) is a novel marker of repolarization instability and strong predictor of death in patients post-myocardial infarction that is believed to occur in association with low-frequency oscillations in sympathetic nerve activity. However, this hypothesis is based on associations of PRD with indices of sympathetic activity that are not directly linked to cardiac function, such as muscle vasoconstrictor activity and the variability of cardiovascular autospectra. In this review article, we critically evaluate existing scientific evidence obtained primarily in experimental animal models, with the aim of identifying the neuronal networks responsible for the generation of low-frequency sympathetic rhythms along the neurocardiac axis. We discuss the functional significance of rhythmic sympathetic activity on neurotransmission efficacy and explore its role in the pathogenesis of ventricular repolarization instability. Most importantly, we discuss important gaps in our knowledge that require further investigation in order to confirm the hypothesis that low frequency cardiac sympathetic oscillations play a causative role in the generation of PRD.
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Affiliation(s)
- Richard Ang
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Nephtali Marina
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Division of Medicine, University College London, London, United Kingdom
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2
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Sympathetic Nerve Activity-Induced Blood Pressure Fluctuations are Stacked on Linearly: A Simulation Study. NEUROPHYSIOLOGY+ 2018. [DOI: 10.1007/s11062-018-9744-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Behuliak M, Bencze M, Polgárová K, Kuneš J, Vaněčková I, Zicha J. Hemodynamic Response to Gabapentin in Conscious Spontaneously Hypertensive Rats. Hypertension 2018; 72:676-685. [DOI: 10.1161/hypertensionaha.118.09909] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Michal Behuliak
- From the Department of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Prague
| | - Michal Bencze
- From the Department of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Prague
| | - Kamila Polgárová
- From the Department of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Prague
| | - Jaroslav Kuneš
- From the Department of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Prague
| | - Ivana Vaněčková
- From the Department of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Prague
| | - Josef Zicha
- From the Department of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Prague
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Guo ZL, Longhurst JC, Tjen-A-Looi SC, Fu LW. elPBN neurons regulate rVLM activity through elPBN-rVLM projections during activation of cardiac sympathetic afferent nerves. Am J Physiol Regul Integr Comp Physiol 2016; 311:R410-25. [PMID: 27225950 PMCID: PMC5008663 DOI: 10.1152/ajpregu.00127.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/16/2016] [Indexed: 11/22/2022]
Abstract
The external lateral parabrachial nucleus (elPBN) within the pons and rostral ventrolateral medulla (rVLM) contributes to central processing of excitatory cardiovascular reflexes during stimulation of cardiac sympathetic afferent nerves (CSAN). However, the importance of elPBN cardiovascular neurons in regulation of rVLM activity during CSAN activation remains unclear. We hypothesized that CSAN stimulation excites the elPBN cardiovascular neurons and, in turn, increases rVLM activity through elPBN-rVLM projections. Compared with controls, in rats subjected to microinjection of retrograde tracer into the rVLM, the numbers of elPBN neurons double-labeled with c-Fos (an immediate early gene) and the tracer were increased after CSAN stimulation (P < 0.05). The majority of these elPBN neurons contain vesicular glutamate transporter 3. In cats, epicardial bradykinin and electrical stimulation of CSAN increased the activity of elPBN cardiovascular neurons, which was attenuated (n = 6, P < 0.05) after blockade of glutamate receptors with iontophoresis of kynurenic acid (Kyn, 25 mM). In separate cats, microinjection of Kyn (1.25 nmol/50 nl) into the elPBN reduced rVLM activity evoked by both bradykinin and electrical stimulation (n = 5, P < 0.05). Excitation of the elPBN with microinjection of dl-homocysteic acid (2 nmol/50 nl) significantly increased basal and CSAN-evoked rVLM activity. However, the enhanced rVLM activity induced by dl-homocysteic acid injected into the elPBN was reversed following iontophoresis of Kyn into the rVLM (n = 7, P < 0.05). These data suggest that cardiac sympathetic afferent stimulation activates cardiovascular neurons in the elPBN and rVLM sequentially through a monosynaptic (glutamatergic) excitatory elPBN-rVLM pathway.
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Affiliation(s)
- Zhi-Ling Guo
- Department of Medicine and Susan-Samueli Center for Integrative Medicine, School of Medicine, University of California at Irvine, Irvine, California
| | - John C Longhurst
- Department of Medicine and Susan-Samueli Center for Integrative Medicine, School of Medicine, University of California at Irvine, Irvine, California
| | - Stephanie C Tjen-A-Looi
- Department of Medicine and Susan-Samueli Center for Integrative Medicine, School of Medicine, University of California at Irvine, Irvine, California
| | - Liang-Wu Fu
- Department of Medicine and Susan-Samueli Center for Integrative Medicine, School of Medicine, University of California at Irvine, Irvine, California
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Braz GRF, Pedroza AA, Nogueira VO, de Vasconcelos Barros MA, de Moura Freitas C, de Brito Alves JL, da Silva AI, Costa-Silva JH, Lagranha CJ. Serotonin modulation in neonatal age does not impair cardiovascular physiology in adult female rats: Hemodynamics and oxidative stress analysis. Life Sci 2016; 145:42-50. [DOI: 10.1016/j.lfs.2015.12.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 12/08/2015] [Accepted: 12/09/2015] [Indexed: 01/06/2023]
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Costa-Silva JH, de Brito-Alves JL, Barros MADV, Nogueira VO, Paulino-Silva KM, de Oliveira-Lira A, Nobre IG, Fragoso J, Leandro CG. New Insights on the Maternal Diet Induced-Hypertension: Potential Role of the Phenotypic Plasticity and Sympathetic-Respiratory Overactivity. Front Physiol 2015; 6:345. [PMID: 26635631 PMCID: PMC4656835 DOI: 10.3389/fphys.2015.00345] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 11/06/2015] [Indexed: 12/25/2022] Open
Abstract
Systemic arterial hypertension (SAH) is an important risk factor for cardiovascular disease and affects worldwide population. Current environment including life style coupled with genetic programming have been attributed to the rising incidence of hypertension. Besides, environmental conditions during perinatal development such as maternal malnutrition can program changes in the integration among renal, neural, and endocrine system leading to hypertension. This phenomenon is termed phenotypic plasticity and refers to the adjustment of a phenotype in response to environmental stimuli without genetic change, following a novel or unusual input during development. Human and animal studies indicate that fetal exposure to an adverse maternal environment may alter the renal morphology and physiology that contribute to the development of hypertension. Recently, it has been shown that the maternal protein restriction alter the central control of SAH by a mechanism that include respiratory dysfunction and enhanced sympathetic-respiratory coupling at early life, which may contribute to adult hypertension. This review will address the new insights on the maternal diet induced-hypertension that include the potential role of the phenotypic plasticity, specifically the perinatal protein malnutrition, and sympathetic-respiratory overactivity.
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Affiliation(s)
- João H Costa-Silva
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - José L de Brito-Alves
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Monique Assis de V Barros
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Viviane Oliveira Nogueira
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Kássya M Paulino-Silva
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Allan de Oliveira-Lira
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Isabele G Nobre
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Jéssica Fragoso
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
| | - Carol G Leandro
- Department of Physical Education and Sport Science, Academic Center of Vitoria, Federal University of Pernambuco Vitória de Santo Antão, Brazil
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Barros MAV, De Brito Alves JL, Nogueira VO, Wanderley AG, Costa-Silva JH. Maternal low-protein diet induces changes in the cardiovascular autonomic modulation in male rat offspring. Nutr Metab Cardiovasc Dis 2015; 25:123-130. [PMID: 25287449 DOI: 10.1016/j.numecd.2014.07.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/16/2014] [Accepted: 07/24/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND AND AIMS Maternal undernutrition induces development of the arterial hypertension. We investigated the effects of a maternal low-protein diet on cardiovascular autonomic control in the offspring. METHODS AND RESULTS Male Wistar rats were divided into two groups according to the diets of their mothers during gestation and lactation: the control (normal protein, NP, 17% casein; n = 14) and low-protein (LP, 8% casein; n = 14) groups. Direct measurements of arterial pressure (AP) were recorded from wakeful 90-day-old male offspring. The LP offspring presented higher mean AP than did the NP rats (NP: 93 ± 4 vs. LP: 113 ± 2 mmHg; p < 0.05), whereas the heart rate (HR) was similar in the two groups. In the spectral analysis, the LP group showed higher power at low (NP: 1.98 ± 0.25 vs. LP: 3.7 ± 0.3 mmHg²; p < 0.05) and high (NP: 1.28 ± 0.18 vs. LP: 2.13 ± 0.42 mmHg²; p < 0.05) frequencies of systolic arterial pressure (SAP). In the pulse interval, the LP group presented an increase in the LF/HF ratio (NP: 0.32 vs. LP: 0.56; p < 0.05). After propranolol (4 mg/kg, intravenous (iv)), the bradycardia was higher in the LP group (NP: -36 ± 8 vs. LP: -94 ± 12 bpm; p < 0.05), after methylatropine (2 mg/kg, iv), the tachycardia was similar to NP group. After administration of the ganglionic blocker (hexamethonium; 25 mg/kg, iv), the LP animals showed larger delta variation in the AP (NP: -33.7 ± 5 vs. LP: -53.6 ± 4 mmHg; p < 0.05). CONCLUSION The rats subjected to protein malnutrition presented an increase in the cardiovascular sympathetic tone, which contributed to the elevated AP observed in these animals.
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Affiliation(s)
- M A V Barros
- Department of Physical Education and Sport Sciences, Academic Center of Vitoria (CAV), Federal University of Pernambuco, 55608-680, Brazil
| | - J L De Brito Alves
- Department of Physical Education and Sport Sciences, Academic Center of Vitoria (CAV), Federal University of Pernambuco, 55608-680, Brazil
| | - V O Nogueira
- Department of Physical Education and Sport Sciences, Academic Center of Vitoria (CAV), Federal University of Pernambuco, 55608-680, Brazil
| | - A G Wanderley
- Department of Physiology and Pharmacology, Federal University of Pernambuco, Brazil
| | - J H Costa-Silva
- Department of Physical Education and Sport Sciences, Academic Center of Vitoria (CAV), Federal University of Pernambuco, 55608-680, Brazil.
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Holbein WW, Bardgett ME, Toney GM. Blood pressure is maintained during dehydration by hypothalamic paraventricular nucleus-driven tonic sympathetic nerve activity. J Physiol 2014; 592:3783-99. [PMID: 24973410 DOI: 10.1113/jphysiol.2014.276261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Resting sympathetic nerve activity (SNA) consists primarily of respiratory and cardiac rhythmic bursts of action potentials. During homeostatic challenges such as dehydration, the hypothalamic paraventricular nucleus (PVN) is activated and drives SNA in support of arterial pressure (AP). Given that PVN neurones project to brainstem cardio-respiratory regions that generate bursting patterns of SNA, we sought to determine the contribution of PVN to support of rhythmic bursting of SNA during dehydration and to elucidate which bursts dominantly contribute to maintenance of AP. Euhydrated (EH) and dehydrated (DH) (48 h water deprived) rats were anaesthetized, bilaterally vagotomized and underwent acute PVN inhibition by bilateral injection of the GABA-A receptor agonist muscimol (0.1 nmol in 50 nl). Consistent with previous studies, muscimol had no effect in EH rats (n = 6), but reduced mean AP (MAP; P < 0.001) and integrated splanchnic SNA (sSNA; P < 0.001) in DH rats (n = 6). Arterial pulse pressure was unaffected in both groups. Muscimol reduced burst frequency of phrenic nerve activity (P < 0.05) equally in both groups without affecting the burst amplitude-duration integral (i.e. area under the curve). PVN inhibition did not affect the amplitude of the inspiratory peak, expiratory trough or expiratory peak of sSNA in either group, but reduced cardiac rhythmic sSNA in DH rats only (P < 0.001). The latter was largely reversed by inflating an aortic cuff to restore MAP (n = 5), suggesting that the muscimol-induced reduction of cardiac rhythmic sSNA in DH rats was an indirect effect of reducing MAP and thus arterial baroreceptor input. We conclude that MAP is largely maintained in anaesthetized DH rats by a PVN-driven component of sSNA that is neither respiratory nor cardiac rhythmic.
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Affiliation(s)
- Walter W Holbein
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
| | - Megan E Bardgett
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
| | - Glenn M Toney
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
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Turner A, Kumar N, Farnham M, Lung M, Pilowsky P, McMullan S. Rostroventrolateral medulla neurons with commissural projections provide input to sympathetic premotor neurons: anatomical and functional evidence. Eur J Neurosci 2013; 38:2504-15. [PMID: 23651135 DOI: 10.1111/ejn.12232] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 03/21/2013] [Accepted: 03/27/2013] [Indexed: 01/09/2023]
Abstract
The activity of neurons in the rostral ventrolateral medulla (RVLM) is critical for the generation of vasomotor sympathetic tone. Multiple pre-sympathetic pathways converge on spinally projecting RVLM neurons, but the origin and circumstances in which such inputs are active are poorly understood. We have previously shown that input from the contralateral brainstem contributes to the baseline activity of this population: in the current study we investigate the distribution, phenotype and functional properties of RVLM neurons with commissural projections in the rat. We firstly used retrograde transport of fluorescent microspheres to identify neurons that project to the contralateral RVLM. Labelled neurons were prominent in a longitudinal column that extended over 1 mm caudal from the facial nucleus and contained hybridisation products indicating enkephalin (27%), GABA (15%) and adrenaline (3%) synthesis and included 6% of bulbospinal neurons identified by transport of cholera toxin B. Anterograde transport of fluorescent dextran-conjugate from the contralateral RVLM revealed extensive inputs throughout the RVLM that frequently terminated in close apposition with catecholaminergic and bulbospinal neurons. In urethane-anaesthetised rats we verified that 28/37 neurons antidromically activated by electrical stimulation of the contralateral pressor region were spontaneously active, of which 13 had activity locked to central respiratory drive and 15 displayed ongoing tonic discharge. In six tonically active neurons sympathoexcitatory roles were indicated by spike-triggered averages of splanchnic sympathetic nerve activity. We conclude that neurons in the RVLM project to the contralateral brainstem, form synapses with sympathetic premotor neurons, and have functional properties consistent with sympthoexcitatory function.
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Affiliation(s)
- Anita Turner
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, 2109, Australia
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Tsai ML, Chen CC, Yeh CJ, Chou LM, Cheng CH. Frequency ranges of heart rate variability related to autonomic nerve activity in the mouse. Clin Exp Hypertens 2011; 34:182-90. [PMID: 21967028 DOI: 10.3109/10641963.2011.577492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mice have gained more and more attention in recent years and been widely used in transgenic experiments. Although the number of researches on the heart rate variability (HRV) of mice has been gradually increasing, a consensus on the frequency ranges of autonomic modulation has not been established. Therefore, the main purpose of this study was to find a HRV "prototype" for conscious mice in the state of being motionless and breathing regularly (called "genuinely resting"), and to determine the frequency ranges corresponding to the autonomic modulation. Further, whether these frequencies will change when the mice move freely was studied to evaluate the feasibility of the HRV spectrum as an index of the autonomic modulation of mice. The recording sites were specially arranged to simultaneously obtain the electrocardiography and electromyography data to be provided for the use of HRV analysis and motion monitoring, respectively. The states of being motionless and breathing regularly as judged from the electromyography results were selected as a genuine resting state of a conscious mouse. The frequencies related to autonomic modulation of HRV were determined by comparing the spectrum changes before and after blockades of the autonomic tone by different pharmaceutical agents in both the genuine resting state and freely moving states. Our results showed that the HRV of mice is not suitable for indexing sympathetic modulation; however, it is possible to use the spectral power in the frequency range between 0.1 and 1 Hz as an index of parasympathetic modulation.
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Affiliation(s)
- Meng-Li Tsai
- Department of Biomechatronic Engineering, National Ilan University, Ilan, Taiwan.
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McMullan S, Pilowsky PM. The effects of baroreceptor stimulation on central respiratory drive: A review. Respir Physiol Neurobiol 2010; 174:37-42. [DOI: 10.1016/j.resp.2010.07.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 06/30/2010] [Accepted: 07/22/2010] [Indexed: 02/07/2023]
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