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Science (New York, N.Y.) Oct 2018Activation of stretch-sensitive baroreceptor neurons exerts acute control over heart rate and blood pressure. Although this homeostatic baroreflex has been described for...
Activation of stretch-sensitive baroreceptor neurons exerts acute control over heart rate and blood pressure. Although this homeostatic baroreflex has been described for more than 80 years, the molecular identity of baroreceptor mechanosensitivity remains unknown. We discovered that mechanically activated ion channels PIEZO1 and PIEZO2 are together required for baroreception. Genetic ablation of both and in the nodose and petrosal sensory ganglia of mice abolished drug-induced baroreflex and aortic depressor nerve activity. Awake, behaving animals that lack had labile hypertension and increased blood pressure variability, consistent with phenotypes in baroreceptor-denervated animals and humans with baroreflex failure. Optogenetic activation of -positive sensory afferents was sufficient to initiate baroreflex in mice. These findings suggest that PIEZO1 and PIEZO2 are the long-sought baroreceptor mechanosensors critical for acute blood pressure control.
Topics: Animals; Baroreflex; Blood Pressure; Ion Channels; Mechanotransduction, Cellular; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Neurons; Nodose Ganglion; Optogenetics; Pressoreceptors
PubMed: 30361375
DOI: 10.1126/science.aau6324 -
The Journal of Physiological Sciences :... Nov 2019This brief review summarizes the current knowledge on sex differences in baroreflex function, with a major focus on studies in humans. It has been demonstrated that... (Review)
Review
This brief review summarizes the current knowledge on sex differences in baroreflex function, with a major focus on studies in humans. It has been demonstrated that healthy women have blunted cardiovagal baroreflx sensitivity during a rapid (i.e., within seconds) hypertensive stimulus, but baroreflex sensitivity is similar between the sexes during a hypotensive stimulus. Normal aging decreases cardiovagal baroreflex sensitivity and the rate of decline is similar in men and women. Cardiovagal baroreflex sensitivity is reduced in pathological conditions such as hypertension and type II diabetes, and the reduction is greater in female patients than male patients. There is no clear sex difference in sympathetic baroreflex sensitivity among young individuals, however, with women of more advanced age, sympathetic baroreflex sensitivity decreases, which appears to be associated with greater arterial stiffness compared with similarly aged men. The blunted sympathetic baroreflex sensitivity in older women may predispose them to an increased prevalence of hypertension and cardiovascular disease.
Topics: Aging; Baroreflex; Cardiovascular Diseases; Female; Humans; Male; Sex Factors; Sympathetic Nervous System
PubMed: 31721084
DOI: 10.1007/s12576-019-00727-z -
Applied Psychophysiology and Biofeedback Dec 2022This paper reviews the published work of me along with my students and close colleagues on the topic of heart rate variability biofeedback (HRVB). It includes early... (Review)
Review
This paper reviews the published work of me along with my students and close colleagues on the topic of heart rate variability biofeedback (HRVB). It includes early research by Vaschillo documenting resonance characteristics of the baroreflex system that causes large oscillations in heart rate when breathing at resonance frequency, research on heart rate variability as a marker of parasympathetic stress response in asthma, and HRVB as a treatment for asthma and depression. Many questions about HRVB remain unresolved, and important questions for future research are listed.
Topics: Humans; Heart Rate; Biofeedback, Psychology; Baroreflex; Respiration; Asthma
PubMed: 35254592
DOI: 10.1007/s10484-022-09535-5 -
Scientific Reports Feb 2023Little is known on the effects of respiratory patterns on baroreflex function in heart failure (HF). Patients with HF (n = 30, age 61.6 ± 10 years,...
Little is known on the effects of respiratory patterns on baroreflex function in heart failure (HF). Patients with HF (n = 30, age 61.6 ± 10 years, mean ± SD) and healthy controls (CNT, n = 10, age 58.9 ± 5.6 years) having their R-R interval (RRI, EKG), systolic arterial blood pressure (SBP, Finapres) and respiratory signal (RSP, Respitrace) monitored, were subjected to three recording sessions: free-breathing, fast- (≥ 12 bpm) and slow- (6 bpm) paced breathing. Baroreflex sensitivity (BRS) and power spectra of RRI, SBP, and RSP signals were calculated. During free-breathing, compared to CNT, HF patients showed a significantly greater modulation of respiratory volumes in the very-low-frequency (< 0.04 Hz) range and their BRS was not significantly different from that of CNT. During fast-paced breathing, when very-low-frequency modulations of respiration were reduced, BRS of HF patients was significantly lower than that of CNT and lower than during free breathing. During slow-paced breathing, BRS became again significantly higher than during fast breathing. In conclusion: (1) in free-breathing HF patients is present a greater modulation of respiratory volumes in the very-low-frequency range; (2) in HF patients modulation of respiration in the very-low and low frequency (around 0.1 Hz) ranges contributes to preserve baroreflex-mediated control of heart rate.
Topics: Humans; Middle Aged; Aged; Baroreflex; Blood Pressure; Respiration; Respiratory Rate; Heart Rate; Heart Failure
PubMed: 36755066
DOI: 10.1038/s41598-023-29271-y -
American Journal of Physiology.... Oct 2002The arterial baroreflex contributes importantly to the short-term regulation of blood pressure and cardiovascular variability. A number of factors (including reflex,... (Review)
Review
The arterial baroreflex contributes importantly to the short-term regulation of blood pressure and cardiovascular variability. A number of factors (including reflex, humoral, behavioral, and environmental) may influence gain and effectiveness of the baroreflex, as well as cardiovascular variability. Many central neural structures are also involved in the regulation of the cardiovascular system and contribute to the integrity of the baroreflex. Consequently, brain injuries or ischemia may induce baroreflex impairment and deranged cardiovascular variability. Baroreflex dysfunction and deranged cardiovascular variability are also common findings in cardiovascular disease. A blunted baroreflex gain and impaired heart rate variability are predictive of poor outcome in patients with heart failure and myocardial infarction and may represent an early index of autonomic activation in left ventricular dysfunction. The mechanisms mediating these relationships are not well understood and may in part be the result of cardiac structural changes and/or altered central neural processing of baroreflex signals.
Topics: Animals; Arteries; Baroreflex; Brain; Cardiovascular Diseases; Cardiovascular Physiological Phenomena; Humans
PubMed: 12228049
DOI: 10.1152/ajpregu.00051.2002 -
American Journal of Physiology.... Jul 2021Obese Zucker rats (OZRs) develop hypertension and hyperinsulinemia by 3 mo of age. Male OZRs also have diminished baroreflex-mediated activation of nucleus tractus...
Obese Zucker rats (OZRs) develop hypertension and hyperinsulinemia by 3 mo of age. Male OZRs also have diminished baroreflex-mediated activation of nucleus tractus solitarius (NTS) and bradycardia, which are improved by correcting their hyperglycemia. Conversely, 3-mo-old female OZRs and lean Zucker rats (LZRs) have equivalent baroreflex-mediated bradycardia that is impaired in 6-mo-old OZRs. We hypothesized that 3-mo-old female OZRs maintain NTS activation and baroreflexes coincident with glycemic control. We also hypothesized that 6-mo-old female OZRs develop impaired baroreflexes with hyperglycemia and diminished NTS activation. In 12- to 16-wk-old females, sympathetic nerve activity (SNA) and arterial pressure (AP) were higher in OZRs than LZRs. However, baroreflex-mediated inhibition of SNA and bradycardia were equivalent in female OZRs and LZRs. Unlike deficits in male OZRs, female OZRs and LZRs had no differences in phenylephrine-induced c-Fos expression in NTS or decreases in SNA and AP evoked by glutamate into NTS. Compared with hyperglycemia in male OZRs (217.9 ± 34.4 mg/dL), female OZRs had normal fed blood glucose levels (108.2 ± 1.6 mg/dL in LZRs and 113.6 ± 3.5 mg/dL in OZRs) with emerging glucose intolerance. Conscious 24- to 27-wk-old female OZRs had impaired baroreflex-mediated bradycardia, but fed blood glucose was modestly elevated (124.2 ± 5.2 mg/dL) and phenylephrine-induced c-Fos expression in NTS was comparable to LZRs. These data suggest that better glycemic control in 3-mo-old female OZRs prevents diminished NTS activation and baroreflexes, supporting the notion that hyperglycemia impairs these responses in male OZRs. However, 6-mo-old female OZRs had impaired baroreflex efficacy without diminished NTS activation or pronounced hyperglycemia, suggesting baroreflex deficits develop by different mechanisms in female and male OZRs.
Topics: Aging; Animals; Baroreflex; Blood Glucose; Cholesterol; Female; Gene Expression Regulation; Glycemic Control; Hyperinsulinism; Hypertension; Insulin; Male; Obesity; Phenylephrine; Proto-Oncogene Proteins c-fos; Rats; Rats, Zucker; Sex Factors; Sympathetic Nervous System; Triglycerides
PubMed: 33978481
DOI: 10.1152/ajpregu.00341.2020 -
Effects of age and sex on vasomotor activity and baroreflex sensitivity during the sleep-wake cycle.Scientific Reports Dec 2022Cardiovascular function is related to age, sex, and state of consciousness. We hypothesized that cardiovagal baroreflex sensitivity (BRS) demonstrates different patterns...
Cardiovascular function is related to age, sex, and state of consciousness. We hypothesized that cardiovagal baroreflex sensitivity (BRS) demonstrates different patterns in both sexes before and after 50 years of age and that these patterns are associated with patterned changes during the sleep-wake cycle. We recruited 67 healthy participants (aged 20-79 years; 41 women) and divided them into four age groups: 20-29, 30-49, 50-69, and 70-79 years. All the participants underwent polysomnography and blood pressure measurements. For each participant, we used the average of the arterial pressure variability, heart rate variability (HRV), and BRS parameters during the sleep-wake stages. BRS and HRV parameters were significantly negatively correlated with age. The BRS indexes were significantly lower in the participants aged ≥ 50 years than in those aged < 50 years, and these age-related declines were more apparent during non-rapid eye movement sleep than during wakefulness. Only BRS demonstrated a significantly negative correlation with age in participants ≥ 50 years old. Women exhibited a stronger association than men between BRS and age and an earlier decline in BRS. Changes in BRS varied with age, sex, and consciousness state, each demonstrating a specific pattern. The age of 50 years appeared to be a crucial turning point for sexual dimorphism in BRS. Baroreflex modulation of the cardiovascular system during sleep sensitively delineated the age- and sex-dependent BRS patterns, highlighting the clinical importance of our results. Our findings may aid in screening for neurocardiac abnormalities in apparently healthy individuals.
Topics: Male; Humans; Female; Young Adult; Adult; Middle Aged; Baroreflex; Sleep; Cardiovascular System; Polysomnography; Heart Rate; Blood Pressure
PubMed: 36575245
DOI: 10.1038/s41598-022-26440-3 -
Zhongguo Yi Xue Ke Xue Yuan Xue Bao.... Aug 2022Heart failure (HF) is the endstage of multiple cardiovascular diseases.Impaired autonomic regulation and sympathetic-parasympathetic imbalance are considered key factors... (Review)
Review
Heart failure (HF) is the endstage of multiple cardiovascular diseases.Impaired autonomic regulation and sympathetic-parasympathetic imbalance are considered key factors in HF progression.Baroreflex activation therapy (BAT),a novel device-based therapy which stimulates the carotid sinuses and regulates autonomic function,has demonstrated good efficacy in treating HF and improving prognosis.This review summarized the results of the latest relevant studies to provide support for further study of BAT.
Topics: Baroreflex; Heart Failure; Humans
PubMed: 36065707
DOI: 10.3881/j.issn.1000-503X.13998 -
Experimental Physiology Jan 2012After considerable debate and key experimental evidence, the importance of the arterial baroreflex in contributing to and maintaining the appropriate neural... (Review)
Review
After considerable debate and key experimental evidence, the importance of the arterial baroreflex in contributing to and maintaining the appropriate neural cardiovascular adjustments to exercise is now well accepted. Indeed, the arterial baroreflex resets during exercise in an intensity-dependent manner to continue to regulate blood pressure as effectively as at rest. Studies have indicated that the exercise resetting of the arterial baroreflex is mediated by both the feedforward mechanism of central command and the feedback mechanism associated with skeletal muscle afferents (the exercise pressor reflex). Another perhaps less appreciated neural mechanism involved in evoking and maintaining neural cardiovascular responses to exercise is the cardiopulmonary baroreflex. The limited information available regarding the cardiopulmonary baroreflex during exercise provides evidence for a role in mediating sympathetic nerve activity and blood pressure responses. In addition, recent investigations have demonstrated an interaction between cardiopulmonary baroreceptors and the arterial baroreflex during dynamic exercise, which contributes to the magnitude of exercise-induced increases in blood pressure as well as the resetting of the arterial baroreflex. Furthermore, neural inputs from the cardiopulmonary baroreceptors appear to play an important role in establishing the operating point of the arterial baroreflex. This symposium review highlights recent studies in these important areas indicating that the interactions of four neural mechanisms (central command, the exercise pressor reflex, the arterial baroreflex and cardiopulmonary baroreflex) are integral in mediating the neural cardiovascular adjustments to exercise.
Topics: Arteries; Baroreflex; Exercise; Heart; Humans; Sympathetic Nervous System
PubMed: 22002871
DOI: 10.1113/expphysiol.2011.057554 -
Clinical Autonomic Research : Official... Feb 2017Obese adults exhibit increased levels of inflammation, which may negatively affect blood pressure regulation. Based on existing literature, we hypothesized: (1)...
PURPOSE
Obese adults exhibit increased levels of inflammation, which may negatively affect blood pressure regulation. Based on existing literature, we hypothesized: (1) baroreflex sensitivity would be lower in obese adults when compared to lean adults; (2) acute ibuprofen (IBU, a cyclooxygenase inhibitor and nonsteroidal antiinflammatory agent) administration would increase baroreflex sensitivity in obese adults, with no effect in lean adults.
METHODS
Seven lean (4 male, 3 female) and six obese (5 M, 1 F) adults completed two visits randomized to control (CON) or IBU (800 mg oral). On each visit, blood pressure (intra-arterial catheter), heart rate (ECG), and muscle sympathetic nerve activity (MSNA, microneurography) were measured continuously. Sympathetic and cardiac baroreflex sensitivities were assessed using the modified Oxford technique.
RESULTS
Measures of systemic inflammation [C-reactive protein (CRP) and interleukin-6 (IL-6)] were higher in obese adults when compared to lean adults and tended to decrease with IBU (IL-6: p < 0.05; CRP: p = 0.14). Cardiac baroreflex sensitivity was lower in obese adults (14 ± 2 vs. 24 ± 2 ms/mmHg, p = 0.02), whereas sympathetic baroreflex sensitivity was higher in obese adults (-3.6 ± 0.5 vs. -2.1 ± 0.5 bursts/100 beats/mmHg, p = 0.03) when compared to lean. There was no effect of IBU on cardiac or sympathetic baroreflex sensitivity in either group (p value range 0.20-0.71).
CONCLUSION
Despite obese individuals exhibiting higher levels of systemic inflammation and lower cardiac baroreflex sensitivity when compared to lean adults, an acute dose of IBU has no effect on cardiac or sympathetic baroreflex sensitivity.
Topics: Adult; Baroreflex; Cyclooxygenase Inhibitors; Female; Humans; Ibuprofen; Male; Obesity; Random Allocation; Thinness
PubMed: 27838779
DOI: 10.1007/s10286-016-0389-z