Influence of ageing on carotid baroreflex peak response latency in humans

Fisher, James; Kim, Areum; Young, Colin N.; Ogoh, Shigehiko; Raven, Peter B.; Secher, Niels H.; Fadel, Paul J.

doi:10.1113/jphysiol.2009.177998

Cited by 32 publications

(26 citation statements)

References 65 publications

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“…However, previous studies examining the influence of age on vascular responses to sympathetic activation have reported both blunted (10) and preserved (14) responses in older individuals. In addition, the reduced BP response to carotid baroreceptor unloading may also be related to an attenuated tachycardic response (18,19). Further work is required to examine the influence of aging on the ABR-regulation of vascular conductance and the relative contribution of central hemodynamics to overall ABR control of BP.…”

Section: Discussionmentioning

confidence: 99%

Carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans

Fisher

Kim²,

Young³

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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Fisher JP, Kim A, Young CN, Fadel PJ. Carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans. Am J Physiol Regul Integr Comp Physiol 299: R1241-R1247, 2010. First published September 8, 2010 doi:10.1152/ajpregu.00462.2010.-The arterial baroreflex is fundamental for evoking and maintaining appropriate cardiovascular adjustments to exercise. We sought to investigate how aging influences carotid baroreflex regulation of blood pressure (BP) during dynamic exercise. BP and heart rate (HR) were continuously recorded at rest and during leg cycling performed at 50% HR reserve in 15 young (22 Ϯ 1 yr) and 11 older (61 Ϯ 2 yr) healthy subjects. Five-second pulses of neck pressure and neck suction from ϩ40 to Ϫ80 Torr were applied to determine the full carotid baroreflex stimulus response curve and examine baroreflex resetting during exercise. Although the maximal gain of the modeled stimulus response curve was similar in both groups at rest and during exercise, in older subjects the operating point (OP) was located further away from the centering point (CP) and toward the reflex threshold, both at rest (OP minus CP; Ϫ10 Ϯ 3 older vs. 0 Ϯ 2 young mmHg, P Ͻ 0.05) and during exercise (OP minus CP; Ϫ10 Ϯ 2 older vs. 1 Ϯ 3 young mmHg, P Ͻ 0.05). In agreement, older subjects demonstrated a reduced BP response to neck pressure (simulated carotid hypotension) and a greater BP response to neck suction (simulated carotid hypertension). In addition, the magnitude of the upward and rightward resetting of the carotid baroreflex-BP stimulus response curve with exercise was ϳ40% greater in older individuals. These data indicate that despite a maintained maximal gain, the ability of the carotid baroreflex to defend against a hypotensive challenge is reduced, whereas responses to hypertensive stimuli are greater with advanced age, both at rest and during exercise. cardiovascular control; autonomic nervous system; baroreflex sensitivity; arterial baroreceptors; total vascular conductance THE ARTERIAL BAROREFLEX (ABR) plays a critical role in the moment-to-moment regulation of arterial blood pressure (BP) via modulation of autonomic neural activity to the heart and vasculature. Although a wealth of data has indicated that aging is associated with impairments in resting cardiac baroreflex function (3,14,19,29), studies examining ABR control of muscle sympathetic nerve activity (SNA) have reported equivocal results demonstrating impaired, preserved, or augmented responsiveness in older healthy adults (11,14,24,29,30,46). Moreover, regarding overall ABR regulation of BP and aging, limited studies have been performed suggesting either reduced (24, 27) or unchanged (4, 41) control with advanced age. Furthermore, to date, the effect of aging on ABR control of BP during dynamic exercise has not been studied. During exercise it has been shown in both animals (1, 8) and young healthy subjects (35, 38) that the ABR continues to regulate BP by resetting to operate around the exercise-induced elevation...

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Section: Discussionmentioning

confidence: 99%

Carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans

Fisher

Kim²,

Young³

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

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“…To accurately quantify the stimulus applied, a silicon piezoresistive pressure sensor (Freescale Semiconductor, Austin, TX) was connected to a port on the collar. To minimize respiratory-related modulation of HR, the 5-s pulses of NS and NP were delivered to the carotid sinus during a brief 12-to 15-s breath hold at end expiration phase (Eckber et al 1980;Fisher et al 2009). Familiarization sessions.…”

Section: Methodsmentioning

confidence: 99%

“…No subject had a history or symptoms of cardiovascular or pulmonary disease. There is compounding evidence to show that sex, age, and race influence carotid baroreceptor function (Credeur et al 2014;Fisher et al 2007Fisher et al , 2009Fisher et al , 2012Holwerda et al 2001Holwerda et al , 2013Kim et al 2011). Thus, in an effort to minimize these variables, each individual with MS was matched to a healthy control of the same sex, age, race, height, and weight.…”

Section: Subjectsmentioning

confidence: 99%

Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis

Huang

Allen

Keller

et al. 2016

Journal of Neurophysiology

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Huang M, Allen DR, Keller DM, Fadel PJ, Frohman EM, Davis SL. Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis. J Neurophysiol 116: 81-87, 2016. First published April 13, 2016 doi:10.1152/jn.00003.2016.-Multiple sclerosis (MS), a progressive neurological disease, can lead to impairments in the autonomic control of cardiovascular function. We tested the hypothesis that individuals with relapsing-remitting MS (n ϭ 10; 7 females, 3 males; 13 Ϯ 4 yr from diagnosis) exhibit impaired carotid baroreflex control of blood pressure and heart rate compared with sex, age, and body weight-matched healthy individuals (CON: n ϭ 10; 7 females, 3 males). At rest, 5-s trials of neck pressure (NP; ϩ40 Torr) and neck suction (NS; Ϫ60 Torr) were applied to simulate carotid hypotension and hypertension, respectively, while mean arterial pressure (MAP; finger photoplethysmography), heart rate (HR), cardiac output (CO; Modelflow), and total vascular conductance (TVC) were continuously measured. In response to NP, there was a blunted increase in peak MAP responses (MS: 5 Ϯ 2 mmHg) in individuals with MS compared with healthy controls (CON: 9 Ϯ 3 mmHg; P ϭ 0.005), whereas peak HR responses were not different between groups. At the peak MAP response to NP, individuals with MS demonstrated an attenuated decrease in TVC (MS, Ϫ10 Ϯ 4% baseline vs. CON, Ϫ15 Ϯ 4% baseline, P ϭ 0.012), whereas changes in CO were similar between groups. Following NS, all cardiovascular responses (i.e., nadir MAP and HR and percent changes in CO and TVC) were not different between MS and CON groups. These data suggest that individuals with MS have impaired carotid baroreflex control of blood pressure via a blunted vascular conductance response resulting in a diminished ability to increase MAP in response to a hypotensive challenge.baroreceptors; heart rate; sympathetic nervous system; carotid hypotension; carotid hypertension MULTIPLE SCLEROSIS (MS), the most common disabling neurological disorder of young adults, is a progressive autoimmune disease affecting the central nervous system (Edmonds et al. 2010). This disease results in the demyelination of axons leading to slowed or blocked nerve conduction and ultimately axonal loss within the brain and spinal cord. Abnormal nerve conduction resulting from demyelination disrupts communication to, from, and within the central nervous system causing a constellation of neurological clinical signs and symptoms (Lubin 2005;Oger 2007).Because the underlying pathophysiology of MS becomes more severe as areas of disease progression get larger and involve more of the central nervous system, it is likely the autonomic nervous system is affected (Lubin 2005). Case in point, impaired autonomic control of cardiovascular function has been reported in up to two-thirds of individuals with MS (Acevedo et al. 2000;Nasseri et al. 1998). The most perilous health-related concern related to this autonomic cardiovascular dysfunction is the prevalence of orthostasis-related symptomology (i.e., orthostat...

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“…Fisher et al (9) demonstrated that the parasympathetic nervous activity blockade of the muscarinic receptors with glycopyrrolate increased the latency of the HR response of carotid baroreflex control in healthy individuals. Since our data show a marked reduction in HF component of RRi, the increased time delay observed in patients with MetS ϩ OSA (Table 3) may be associated to reduced cardiac parasympathetic modulation.…”

Section: Discussionmentioning

confidence: 99%

Time delay of baroreflex control and oscillatory pattern of sympathetic activity in patients with metabolic syndrome and obstructive sleep apnea

Toschi‐Dias

Trombetta

Silva

et al. 2013

American Journal of Physiology-Heart and Circulatory Physiology

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Toschi-Dias E, Trombetta IC, Dias da Silva VJ, Maki-Nunes C, Cepeda FX, Alves MJ, Drager LF, Lorenzi-Filho G, Negrao CE, Rondon MU. Time delay of baroreflex control and oscillatory pattern of sympathetic activity in patients with metabolic syndrome and obstructive sleep apnea. Am J Physiol Heart Circ Physiol 304: H1038-H1044, 2013. First published January 25, 2013; doi:10.1152/ajpheart.00848.2012.-The incidence and strength of muscle sympathetic nerve activity (MSNA) depend on the magnitude (gain) and latency (time delay) of the arterial baroreflex control (ABR). However, the impact of metabolic syndrome (MetS) and obstructive sleep apnea (OSA) on oscillatory pattern of MSNA and time delay of the ABR of sympathetic activity is unknown. We tested the hypothesis that MetS and OSA would impair the oscillatory pattern of MSNA and the time delay of the ABR of sympathetic activity. Forty-three patients with MetS were allocated into two groups according to the presence of OSA (MetS ϩ OSA, n ϭ 21; and MetS Ϫ OSA, n ϭ 22). Twelve aged-paired healthy controls (C) were also studied. OSA (apnea-hypopnea index Ͼ 15 events/h) was diagnosed by polysomnography. We recorded MSNA (microneurography), blood pressure (beat-to-beat basis), and heart rate (EKG). Oscillatory pattern of MSNA was evaluated by autoregressive spectral analysis and the ABR of MSNA (ABR MSNA, sensitivity and time delay) by bivariate autoregressive analysis. Patients with MetS ϩ OSA had decreased oscillatory pattern of MSNA compared with MetS Ϫ OSA (P Ͻ 0.01) and C (P Ͻ 0.001). The sensitivity of the ABR MSNA was lower and the time delay was greater in MetS ϩ OSA compared with MetS Ϫ OSA (P Ͻ 0.001 and P Ͻ 0.01, respectively) and C (P Ͻ 0.001 and P Ͻ 0.001, respectively). Patients with MetS Ϫ OSA showed decreased oscillatory pattern of MSNA compared with C (P Ͻ 0.01). The sensitivity of the ABR MSNA was lower in MetS Ϫ OSA than in C group (P Ͻ 0.001). In conclusion, MetS decreases the oscillatory pattern of MSNA and the magnitude of the ABR MSNA. OSA exacerbates these autonomic dysfunctions and further increases the time delay of the baroreflex response of MSNA. latency of baroreflex control; muscle sympathetic nerve activity variability; heart rate variability SYMPATHETIC NERVE ACTIVITY is increased in patients with metabolic syndrome (MetS) (11,22), which enhances the risk of cardiovascular disease and likely cardiac death (5,20,21). Obstructive sleep apnea (OSA), a frequent comorbidity in patients with MetS (8), is characterized by recurrent episodes of partial or complete upper airway obstruction during sleep, leading to intermittent hypoxemia and frequent arousals from sleep (40). Additionally, OSA exacerbates the muscle sympathetic nerve activity (MSNA) in patients with MetS (12, 37) and impairs arterial baroreflex control (ABR) of heart rate (HR) (12, 37). Grassi et al. (12) demonstrated that ABR of HR was further decreased in patients with MetS and OSA. We confirmed that OSA exacerbates the dysfunction of the ABR of HR in patients with MetS (37).The ...

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Influence of ageing on carotid baroreflex peak response latency in humans

Cited by 32 publications

References 65 publications

Carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans

Carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans

Impaired carotid baroreflex control of arterial blood pressure in multiple sclerosis

Time delay of baroreflex control and oscillatory pattern of sympathetic activity in patients with metabolic syndrome and obstructive sleep apnea

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