Baroreceptors

BACKGROUND: Central Illustration : Percutaneous Strategies in Structural Heart Diseases: Focus on Chronic Heart Failure Transcatheter devices for monitoring and treating advanced chronic heart failure patients. PA: pulmonary artery; LA: left atrium; AFR: atrial flow regulator; TASS: Transcatheter Atrial Shunt System; VNS: vagus nerve stimulation; BAT: baroreceptor activation therapy; RDN: renal sympathetic denervation; F: approval by the American regulatory agency (FDA); E: approval by the European regulatory agency (CE Mark)...

eNOS (NOS3) is the enzyme that generates nitric oxide, a signalling molecule and regulator of vascular tone. Loss of eNOS function is associated with increased susceptibility to atherosclerosis, hypertension, thrombosis and stroke. Aortopathy and cardiac hypertrophy have also been found in eNOS null mice, but their aetiology is unclear. We evaluated eNOS nulls before and around birth for cardiac defects, revealing severe abnormalities in the ventricular myocardium and pharyngeal arch arteries. Moreover, baroreceptors in the aortic arch, which sense changes in blood pressure, were reduced...

The sensitization and hypertonicity of visceral afferents are highly relevant to the development and progression of cardiovascular and respiratory disease states. In this review, we described the evidence that the inflammatory process regulates visceral afferent sensitivity and tonicity, affecting the control of the cardiovascular and respiratory system. Some inflammatory mediators like nitric oxide, angiotensin II, endothelin-1, and arginine vasopressin may inhibit baroreceptor afferents and contribute to the baroreflex impairment observed in cardiovascular diseases...

Baroreceptors, sensors that play a role in controlling arterial blood pressure (BP), are mechanical stretch receptors located in the aortic arch and carotid sinuses. Factors affecting the degree of stretch in the vessel wall with BP, such as increased arterial stiffness, may compromise baroreceptor sensitivity (BRS) to BP changes. Yet, evidence of this is scattered, as both baroreceptor sensitivity (BRS) and arterial stiffness are calculated variables with multiple methodological approaches. This pilot study (n=10) investigates the correlation of arterial stiffness and BRS using multiple BRS calculation techniques (spectral and sequence methodologies at aortic and finger sites) and arterial stiffness measurement [carotid-femoral pulse wave velocity (cfPWV), carotid compliance and distensibility]...

Aging is accompanied by considerable deterioration of homeostatic systems, such as autonomic imbalance characterized by heightened sympathetic activity, lower parasympathetic tone, and depressed heart rate (HR) variability, which are aggravated by hypertension. Here, we hypothesized that these age-related deficits in aged hypertensive rats can be ameliorated by exercise training, with benefits to the cardiovascular system. Therefore, male 22 month-old Spontaneously Hypertensive Rats (SHR) and age-matched Wistar Kyoto (WKY) submitted to moderate-intensity exercise training (T) or kept sedentary (S) for 8 weeks were evaluated for hemodynamic/autonomic parameters, baroreflex sensitivity, cardiac sympathetic/parasympathetic tone and analysis of dopamine β-hydroxylase (DBH) and oxytocin (OT) pathways of autonomic brain nuclei...

Although Gaussian white noise (GWN) inputs offer a theoretical framework for identifying higher-order nonlinearity, an actual application to the data of the neural arc of the carotid sinus baroreflex did not succeed in fully predicting the well-known sigmoidal nonlinearity. In the present study, we assumed that the neural arc can be approximated by a cascade of a linear dynamic (LD) component and a nonlinear static (NS) component. We analyzed the data obtained using GWN inputs with a mean of 120 mmHg and standard deviations (SDs) of 10, 20, and 30 mmHg for 15 min each in anesthetized rats (n = 7)...

Many patients with orthotopic heart transplantation later undergo non-cardiac surgery. Historically, neuraxial anaesthesia has been avoided in these patients because the denervated heart is unable to compensate for hypotension via the baroreceptor reflex. Here, we present the cases of two patients with prior heart transplantation who underwent total hip arthroplasty under spinal anaesthesia with intravenous sedation. In both cases, this technique was well-tolerated haemodynamically. We propose that spinal anaesthesia with intravenous sedation can be a safe and efficacious anaesthetic technique for selected patients with a history of orthotopic heart transplantation, with careful intraoperative fluid and pharmacological management...

Functional capacity remains limited in heart failure patients with left ventricular assist devices (LVADs) due to fixed pump speed and inability to offload the left ventricle adequately. We hypothesized that manually adjusting LVAD speed during exercise based on pulmonary capillary wedge pressures would increase total cardiac output and maximal oxygen consumption. Two participants with a HeartWare LVAD underwent an invasive ramp study at rest followed by an invasive cardiopulmonary stress test exercising in two randomized phases: fixed speed and adjusted speed...

UNLABELLED: The temporal response of changes in renal sodium reabsorption during increased renal sympathetic nerve activity has not been investigated. Central hypovolemia by application of lower-body negative-pressure (LBNP) elicits baroreceptor mediated sympathetic reflexes to maintain arterial blood pressure. We hypothesized, that during 90 min LBNP, the renal sodium retention would increase rapidly, remain increased during intervention, and return to baseline immediately after end of intervention...

BACKGROUND: The autonomic nervous system (ANS) plays a significant role in atrial fibrillation (AF). Catheter ablation (CA) affects the ANS balance. The assessment of baroreceptor (BR) function is an established method to measure parasympathetic activity; however, it has been rarely used in patients undergoing CA of AF. AIMS: This study is to assess changes in BR function caused by CA and to compare these changes between two different types of CA: point-by-point radiofrequency (RF) versus cryoballoon (CB)...

BACKGROUND: Autonomic imbalance represents a keystone of chronic heart failure (HF) with substantial clinical and prognostic implications. Baroreceptor activation therapy (BAT) is a new therapeutic strategy to target the autonomic dysbalance by electrical stimulation of carotid baroreceptors. Besides its known beneficial effects on HF parameters, BAT is also supposed to trigger potential antiarrhythmic effects, which may additionally contribute to HF improvement. CASE SUMMARY: We report on a 70-year-old male with progredient shortness of breath and advanced HF in the context of an extensive cardiovascular history...

Electrode-based electrophysiological interfaces with peripheral nerves have come a long way since the 1960s, with several neurostimulation applications witnessing widespread clinical implementation since then. In resistant hypertension, previous clinical trials have shown that "carotid" baroreflex stimulation using device-based baroreflex activation therapy (BAT) can effectively lower blood pressure (BP). However, device-based "aortic" baroreflex stimulation remains untouched for clinical translation. The rat is a remarkable animal model that facilitates exploration of mechanisms pertaining to the baroreceptor reflex and preclinical development of novel therapeutic strategies for BP modulation and hypertension treatment...

Herein, we provide evidence that human regulation of aqueous outflow is by a pump-conduit system similar to that of the lymphatics. Direct observation documents pulsatile aqueous flow into Schlemm's canal and from the canal into collector channels, intrascleral channels, aqueous veins, and episcleral veins. Pulsatile flow in vessels requires a driving force, a chamber with mobile walls and valves. We demonstrate that the trabecular meshwork acts as a deformable, mobile wall of a chamber: Schlemm's canal. A tight linkage between the driving force of intraocular pressure and meshwork deformation causes tissue responses in milliseconds...

AIM: The carotid sinuses and aortic arch are baroreceptor-resident arteries (BRAs) and atherosclerosis-susceptible sites of brain-supplying arteries, which would impair baroreflex-mediated blood pressure (BP) regulation and prompt coronary atherosclerosis. We sought to determine the relationship between total atherosclerosis burden (TAB) of BRAs and coronary atherosclerosis burden (AB) in patients with ischemic cerebrovascular disease (ICVD) and explore the potential contribution of BP profiles to this relationship...

OBJECTIVE: To assess whether local anesthetic infiltration could minimize the carotid baroreceptor reflex (CBR) which has an incidence after carotid artery stenting (CAS) that varies from 29% to 51%. METHODS: This retrospective single-center study included 51 patients (mean age, 70.47 years) who underwent CAS for carotid stenosis. The groups included patients who underwent CAS for asymptomatic ischemic stroke (n=41) or symptomatic disease (n=10). Preprocedural percutaneous lidocaine injections (PPLIs) were administered to 70...

BACKGROUND: Blood pressure (BP) responses to sodium intake show great variation, discriminating salt sensitive (SS) individuals from salt resistant (SR). The pathophysiology behind salt sensitivity is still not fully elucidated. We aimed to investigate salt-induced effects on body fluid, vascular tone and autonomic cardiac response with regard to BP change in healthy normotensive individuals. METHODS: We performed a randomized cross-over study in 51 normotensive individuals with normal BMI and eGFR...

Interoceptive cardiac arousal signals (e.g., from baroreceptor firing at ventricular systole compared to diastole) have been found to enhance perception of fearful versus neutral faces. They have also been found to amplify racially biased misidentification of tools as weapons when preceded by facial images of Black versus White individuals. Since pupil size is strongly coupled to arousal, we tested if experimental manipulation of pupil size influences fear processing in emotional judgement and racial bias tasks involving measurement of cardiac signals...

The abnormal neural control of atria has been considered one of the mechanisms of paroxysmal atrial fibrillation (PAF) pathogenesis. The baroreceptor reflex has an important role in cardiovascular regulation and may serve as an index of autonomic function. This study aimed to analyze the baroreceptor reflex's role in heart rate regulation during upright tilt (HUT) in patients with lone PAF. The study included 68 patients with lone PAF and 34 healthy individuals who underwent baroreflex assessment. Parameters such as baroreflex sensitivity (BRS), number of systolic blood pressure (BP) ramps, and the baroreflex effectiveness index (BEI) were evaluated...

Introduction Epipharyngeal Abrasive Therapy (EAT) has been used as a treatment for chronic epipharyngitis, and although autonomic nerve stimulation has been pointed out as one of the mechanisms by which EAT produces therapeutic effects, there have been few reports examining this mechanism of action. This study investigated the effects of repeated EAT on autonomic nervous system activity in chronic epipharyngitis patients over time, using heart rate variability analysis. In addition, we conducted a loading test using the active standing test (AS test) to examine the effects of EAT on the baroreceptor reflex (BR)...

The purpose of these experiments was to determine if the increase in vascular conductance following a single muscle contraction (50% MVC) (6 male & 6 female subjects) was altered by baroceptor loading and unloading. Rapid onset vasodilation (ROV) was determined by measuring brachial artery blood flow (Doppler ultrasound), and blood pressure (Finapress). Brachial artery vascular conductance was calculated dividing blood flow by mean arterial pressure. ROV was described by the area under the ∆VC-time curve during the 30 s following muscle contraction...