scholarly journals Angiotensin II and the Cardiac Parasympathetic Nervous System in Hypertension

2021 ◽  
Vol 22 (22) ◽  
pp. 12305
Author(s):  
Julia Shanks ◽  
Rohit Ramchandra
Keyword(s):  
Nervous System ◽  
Parasympathetic Nervous System ◽  
Angiotensin Receptor Blockers ◽  
Critical Role ◽  
Brain Regions ◽  
Nerve Endings ◽  
Vagal Activity ◽  
Ang Ii ◽  
Baroreflex Control ◽  
Parasympathetic Nerve

The renin–angiotensin–aldosterone system (RAAS) impacts cardiovascular homeostasis via direct actions on peripheral blood vessels and via modulation of the autonomic nervous system. To date, research has primarily focused on the actions of the RAAS on the sympathetic nervous system. Here, we review the critical role of the RAAS on parasympathetic nerve function during normal physiology and its role in cardiovascular disease, focusing on hypertension. Angiotensin (Ang) II receptors are present throughout the parasympathetic nerves and can modulate vagal activity via actions at the level of the nerve endings as well as via the circumventricular organs and as a neuromodulator acting within brain regions. There is tonic inhibition of cardiac vagal tone by endogenous Ang II. We review the actions of Ang II via peripheral nerve endings as well as via central actions on brain regions. We review the evidence that Ang II modulates arterial baroreflex function and examine the pathways via which Ang II can modulate baroreflex control of cardiac vagal drive. Although there is evidence that Ang II can modulate parasympathetic activity and has the potential to contribute to impaired baseline levels and impaired baroreflex control during hypertension, the exact central regions where Ang II acts need further investigation. The beneficial actions of angiotensin receptor blockers in hypertension may be mediated in part via actions on the parasympathetic nervous system. We highlight important unknown questions about the interaction between the RAAS and the parasympathetic nervous system and conclude that this remains an important area where future research is needed.

Abstract P161: Tai Chi Movements Bring On Parasympathetic Nerve Output As Indicated By Audible Bowel Sounds

Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Desuo Wang
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Tai Chi ◽  
Parasympathetic Nervous System ◽  
Autonomic Nerve ◽  
Parasympathetic Nerve ◽  
Bowel Sounds ◽  
Sympathetic Nervous ◽  
Tai Chi Exercise

Tai Chi movements are unique exercise that can improve cognition, strength somatomotor coordination, and enhance autonomic nerve regulation on internal organ function. The mild increase in heart rate and/or slight sweat during and after practicing Tai Chi indicates the activation of the sympathetic nervous system. There is lack of evidence to show that Tai Chi exercise enhances the activity of parasympathetic nervous system though it has been claimed that practicing Tai Chi could do so. The author tested the hypothesis that Tai Chi exercise brings on an increase in parasympathetic nerve outputs (PNO). The PNO is evaluated by recording the bowel sounds using an audio recorder (Sony digital voice recorder ICD-PX Series) and the data analyses were done using NCH software (WavePad audio editor). The heart rate was simultaneously recorded using a fingertip pulse oximeter (Zacurate Pro Series 500DL) during Tai Chi exercise. All the data was repeatedly collected from a Tai Chi Master in a study period of 6 months. A total of 30 recordings were used to carry out the analysis. The audible bowel sounds occurred when the performer started to do the Ready-Movement of Yang-style Tai Chi. These Tai Chi induced-bowel sounds lasted from the beginning to the end of a set of movements (3-5 min for 24-moves style). The frequency of bowel sounds was in a range of 0.2 to 3.5 Hz. The average number of bowel sounds was approximately 2.5 sounds per Tai Chi Move. The intensity and frequency of the bowel sounds are not related to the change of the performer’s heart rate. In comparison, meditation or deep squat exercise performed by the Tai Chi master did not cause any changes in the bowel sounds. According to the autonomic innervation of the GI tract, increase of bowel movements is mediated by PNO. In conclusion, Tai Chi movements can simultaneously exercise skeletal muscles, sympathetic nervous system and parasympathetic nervous system. The enhancement of parasympathetic nervous system output by Tai Chi exercise is a valuable modality of physical exercise for wellness.

Baroreceptor reflex modulation by circulating angiotensin II is mediated by AT1 receptors in the nucleus tractus solitarius

2007 ◽  
Vol 293 (6) ◽  
pp. R2267-R2278 ◽  
Author(s):  
Peter S. P. Tan ◽  
Suzanne Killinger ◽  
Jouji Horiuchi ◽  
Roger A. L. Dampney
Keyword(s):  
Nucleus Tractus Solitarius ◽  
Area Postrema ◽  
Critical Role ◽  
Baroreceptor Reflex ◽  
Reflex Modulation ◽  
Ang Ii ◽  
Baroreflex Control ◽  
Background Infusion ◽  
Continuous Background

Circulating ANG II modulates the baroreceptor reflex control of heart rate (HR), at least partly via activation of ANG II type 1 (AT1) receptors on neurons in the area postrema. In this study, we tested the hypothesis that the effects of circulating ANG II on the baroreflex also depend on AT1 receptors within the nucleus tractus solitarius (NTS). In confirmation of previous studies in other species, increases in arterial pressure induced by intravenous infusion of ANG II had little effect on HR in urethane-anesthetized rats, in contrast to the marked bradycardia evoked by equipressor infusion of phenylephrine. In the presence of a continuous background infusion of ANG II, the baroreflex control of HR was shifted to higher levels of HR but had little effect on the baroreflex control of renal sympathetic activity. The modulatory effects of circulating ANG II on the cardiac baroreflex were significantly reduced by microinjection of candesartan, an AT1 receptor antagonist, into the area postrema and virtually abolished by microinjections of candesartan into the medial NTS. After acute ablation of the area postrema, a background infusion of ANG II still caused an upward shift of the cardiac baroreflex curve, which was reversed by subsequent microinjection of candesartan into the medial NTS. The results indicate that AT1 receptors in the medial NTS play a critical role in modulation of the cardiac baroreflex by circulating ANG II via mechanisms that are at least partly independent of AT1 receptors in the area postrema.

scholarly journals Heart rate variability in children with type 1 diabetes mellitus

2014 ◽  
Vol 32 (2) ◽  
pp. 279-285 ◽  
Author(s):  
Camila Balsamo Gardim ◽  
Bruno Affonso P. de Oliveira ◽  
Aline Fernanda B. Bernardo ◽  
Rayana Loch Gomes ◽  
Francis Lopes Pacagnelli ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Type 1 Diabetes ◽  
Nervous System ◽  
Type 1 Diabetes Mellitus ◽  
Parasympathetic Nervous System ◽  
Vagal Activity ◽  
Mesh Terms

OBJECTIVE:To gather current information about the effects of type 1 diabetes mellitus on children's cardiac autonomic behavior.DATA SOURCES: The search of articles was conducted on PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO and PEDro databases using the MeSH terms: "autonomic nervous system", "diabetes mellitus", "child", "type 1 diabetes mellitus", "sympathetic nervous system" and "parasympathetic nervous system", and their respective versions in Portuguese (DeCS). Articles published from January 2003 to February 2013 that enrolled children with 9-12 years old with type 1 diabetes mellitus were included in the review.DATA SYNTHESIS: The electronic search resulted in four articles that approached the heart rate variability in children with type 1 diabetes mellitus, showing that, in general, these children present decreased global heart rate variability and vagal activity. The practice of physical activity promoted benefits for these individuals.CONCLUSIONS: Children with type 1 diabetes mellitus present changes on autonomic modulation, indicating the need for early attention to avoid future complications in this group.

Effect of aging on baroreflex function in humans

2007 ◽  
Vol 293 (1) ◽  
pp. R3-R12 ◽  
Author(s):  
Kevin D. Monahan
Keyword(s):  
Nervous System ◽  
Parasympathetic Nervous System ◽  
Pressor Response ◽  
Baroreflex Control ◽  
Arterial Blood ◽  
Impaired Ability ◽  
Baroreflex Function ◽  
Increased Risk ◽  
Vascular Stiffening ◽  
Effects Of Aging

Arterial blood pressure (BP) is regulated via the interaction of various local, humoral, and neural factors. In humans, the major neural pathway for acute BP regulation involves the baroreflexes. In response to baroreceptor activation/deactivation, as occurs during transient changes in BP, key determinants of BP, such as cardiac period/heart rate (via the sympathetic and parasympathetic nervous system) and vascular resistance (via the sympathetic nervous system), are modified to maintain BP homeostasis. In this review, the effects of aging on both the parasympathetic and sympathetic arms of the baroreflex are discussed. Aging is associated with decreased cardiovagal baroreflex sensitivity (i.e., blunted reflex changes in R-R interval in response to a change in BP). Mechanisms underlying this decrease may involve factors such as increased levels of oxidative stress, vascular stiffening, and decreased cardiac cholinergic responsiveness with age. Consequences of cardiovagal baroreflex impairment may include increased levels of BP variability, an impaired ability to respond to acute challenges to the maintenance of BP, and increased risk of sudden cardiac death. In contrast, baroreflex control of sympathetic outflow is not impaired with age. Collectively, changes in baroreflex function with age are associated with an impaired ability of the organism to buffer changes in BP. This is evidenced by the reduced potentiation of the pressor response to bolus infusion of a pressor drug after compared to before systemic ganglionic blockade in older compared with young adults.

Pharmacological Actions of "Kyushin," a Drug Containing Toad Venom (3): Effects on Experimentally Induced Arrhythmia

1993 ◽  
Vol 21 (02) ◽  
pp. 139-149
Author(s):  
Shin-ichi Morishita ◽  
Chishio Sugimoto ◽  
Masarnichi Shoji ◽  
Yasuharu Hirai ◽  
Yasuhiro Oguni ◽  
...  
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Parasympathetic Nervous System ◽  
Inhibitory Effect ◽  
Conduction System ◽  
Pharmacological Effects ◽  
Maximal Concentration ◽  
Parasympathetic Nerve ◽  
Toad Venom ◽  
Intraduodenal Administration

The pharmacological effects of the toad venom-containing drug "Kyushin" on aconitine- and thyroxine-induced arrhythmia in guinea pigs, on the conduction system in Langendorff preparations of rabbit hearts and on the autonomic nervous system in cats were studied. "Kyushin" significantly inhibited the aconitine-induced arrhythmia after intraduodenal administration (i.d.) with 80 mg/kg, and the thyroxine-induced arrhythmia with 40 mg/kg i.d. Although "Kyushin" itself did not affect the conduction system with 30 mg/ml of the maximal concentration being able to be prepared, bufalin and cinobufagin as constituents of toad venom produced inhibition with 0.3 mg/ml and 1 mg/ml, respectively. The decrease in heart rate induced by electrical stimulation to the parasympathetic nerve (vagus nerve) was potentiated by "Kyushin" at 30 mg/kg i.d. The anti-arrhythmic effects of "Kyushin" may be attributable to both possible inhibitory effect on the conduction system and potentiating effect on the parasympathetic nervous system.

scholarly journals Brain angiotensin converting enzyme-2 in central cardiovascular regulation

2020 ◽  
Vol 134 (19) ◽  
pp. 2535-2547
Author(s):  
Mazher Mohammed ◽  
Clara Berdasco ◽  
Eric Lazartigues
Keyword(s):  
Nervous System ◽  
Renin Angiotensin System ◽  
Cardiovascular Effects ◽  
Cardiovascular Regulation ◽  
Brain Regions ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Beneficial Effects ◽  
Recent Developments ◽  
Neuro Inflammation

Abstract The brain renin–angiotensin system (RAS) plays an important role in the regulation of autonomic and neuroendocrine functions, and maintains cardiovascular homeostasis. Ang-II is the major effector molecule of RAS and exerts most of its physiological functions, including blood pressure (BP) regulation, via activation of AT1 receptors. Dysregulation of brain RAS in the central nervous system results in increased Ang-II synthesis that leads to sympathetic outflow and hypertension. Brain angiotensin (Ang) converting enzyme-2 (ACE2) was discovered two decades ago as an RAS component, exhibiting a counter-regulatory role and opposing the adverse cardiovascular effects produced by Ang-II. Studies using synthetic compounds that can sustain the elevation of ACE2 activity or genetically overexpressed ACE2 in specific brain regions found various beneficial effects on cardiovascular function. More recently, ACE2 has been shown to play critical roles in neuro-inflammation, gut dysbiosis and the regulation of stress and anxiety-like behaviors. In the present review, we aim to highlight the anatomical locations and functional implication of brain ACE2 related to its BP regulation via modulation of the sympathetic nervous system and discuss the recent developments and future directions in the ACE2-mediated central cardiovascular regulation.

Parasympathetic impairment of baroreflex control of heart rate in Dahl S rats

1990 ◽  
Vol 259 (1) ◽  
pp. R76-R83 ◽  
Author(s):  
S. A. Whitescarver ◽  
C. E. Ott ◽  
T. A. Kotchen
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Sodium Nitroprusside ◽  
Baroreflex Sensitivity ◽  
Parasympathetic Nervous System ◽  
Baroreflex Control ◽  
High Salt Diet ◽  
Salt Diet ◽  
Reflex Bradycardia ◽  
Before And After

To test the hypothesis that impaired baroreflex control of heart rate in Dahl salt-sensitive (S) rats is due to an impairment of the parasympathetic limb of the bradycardic response, baroreflex sensitivity was evaluated in conscious, chronically instrumented Dahl S and salt-resistant (R) animals. Sensitivity was impaired in Dahl S rats when bolus doses of phenylephrine were administered (0.863 +/- 0.042 vs. 1.43 +/- 0.055 ms/mmHg), but it was not different than in R rats when tested with sodium nitroprusside. When the sensitivities before and after blocking the parasympathetic nervous system with atropine were compared, it was revealed that 82% of the reflex bradycardia resulting from bolus doses of phenylephrine was due to the parasympathetic nervous system, whereas the majority (73%) of the bradycardia induced by 5-min infusions of phenylephrine was due to withdrawal of sympathetic tone. Neither baroreflex sensitivity to infusions of phenylephrine (73% sympathetic) or to infusions after atropine (100% sympathetic) were significantly different between S and R rats. Therefore, the impairment of the heart rate reflex in Dahl S rats is due to an impairment of the parasympathetic limb of the response. In addition, a high-salt diet before the development of hypertension did not alter baroreflex sensitivity in either Dahl S or R rats.

IDENTIFYING DEEP BREATH EFFECT ON CARDIOVASCULAR SIGNALS USING CONDITIONAL ENTROPY: AN INFORMATION DOMAIN APPROACH

2018 ◽  
Vol 30 (02) ◽  
pp. 1850012 ◽  
Author(s):  
M. C. Helen Mary ◽  
Dilbag Singh ◽  
K. K. Deepak
Keyword(s):  
Nervous System ◽  
Respiration Rate ◽  
Information Flow ◽  
Parasympathetic Nervous System ◽  
Conditional Entropy ◽  
Deep Breathing ◽  
Sinus Arrhythmia ◽  
Parasympathetic Nerve ◽  
Normal Breathing ◽  
Information Domain

This quantitative study identifies the coupling changes occurring among cardiac (RR), vascular (SBP) and respiratory (RESP) signals during deep breathing. The deep breathing measures the dysfunction of the parasympathetic autonomic nervous system. The traditional methods based on cross-correlation and coherence analysis lack to measure nonlinear structures and unpredictability of physiological subsystems. Therefore, information domain coupling method based on conditional entropy is proposed to detect the coupling changes. Thirty healthy volunteers were examined for 5[Formula: see text]min at normal breathing and 5[Formula: see text]min during deep breathing (6[Formula: see text]cycles/min). The reduction in respiration rate detects a significant increase in information flow from RESP to RR, RESP to SBP and SBP to RR. The increased interaction from RESP to RR and RESP to SBP at reduced respiration rate indicates the enhancement of respiratory sinus arrhythmia that results in the activation of the parasympathetic nervous system. Also, the balanced cardiovascular interaction observed on normal breathing from RR to SBP disappears, but interaction occurring in baroreflex direction (SBP to RR) increases that helps in the reduction of blood pressure during deep breathing. This detected direction of information flow helps in identifying the coupling changes occurring during parasympathetic nerve activity.

RAS in the Central Nervous System: Potential Role in Neuropsychiatric Disorders

2018 ◽  
Vol 25 (28) ◽  
pp. 3333-3352 ◽  
Author(s):  
Natalia Pessoa Rocha ◽  
Ana Cristina Simoes e Silva ◽  
Thiago Ruiz Rodrigues Prestes ◽  
Victor Feracin ◽  
Caroline Amaral Machado ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Central Nervous System ◽  
Nervous System ◽  
Therapeutic Potential ◽  
Neuropsychiatric Disorders ◽  
Extensive Literature ◽  
Ang Ii ◽  
Mas Receptor ◽  
The Central Nervous System ◽  
The Brain

Background: The Renin-Angiotensin System (RAS) is a key regulator of cardiovascular and renal homeostasis, but also plays important roles in mediating physiological functions in the central nervous system (CNS). The effects of the RAS were classically described as mediated by angiotensin (Ang) II via angiotensin type 1 (AT1) receptors. However, another arm of the RAS formed by the angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and the Mas receptor has been a matter of investigation due to its important physiological roles, usually counterbalancing the classical effects exerted by Ang II. Objective: We aim to provide an overview of effects elicited by the RAS, especially Ang-(1-7), in the brain. We also aim to discuss the therapeutic potential for neuropsychiatric disorders for the modulation of RAS. Method: We carried out an extensive literature search in PubMed central. Results: Within the brain, Ang-(1-7) contributes to the regulation of blood pressure by acting at regions that control cardiovascular functions. In contrast with Ang II, Ang-(1-7) improves baroreflex sensitivity and plays an inhibitory role in hypothalamic noradrenergic neurotransmission. Ang-(1-7) not only exerts effects related to blood pressure regulation, but also acts as a neuroprotective component of the RAS, for instance, by reducing cerebral infarct size, inflammation, oxidative stress and neuronal apoptosis. Conclusion: Pre-clinical evidence supports a relevant role for ACE2/Ang-(1-7)/Mas receptor axis in several neuropsychiatric conditions, including stress-related and mood disorders, cerebrovascular ischemic and hemorrhagic lesions and neurodegenerative diseases. However, very few data are available regarding the ACE2/Ang-(1-7)/Mas receptor axis in human CNS.

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