Baroreflex Sensitivity

Rovere, Maria Teresa La; Mortara, Andrea; Schwartz, Peter J.

doi:10.1111/j.1540-8167.1995.tb00452.x

Cited by 72 publications

(63 citation statements)

References 69 publications

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“…[21,36] BRS, a well-established index of cardiac vagal responsiveness [37], has been shown to be depressed during sleep in patients with severe OSAS, and uncontrolled short-term trials have suggested an improvement of nocturnal BRS with CPAP treatment [7][8][9]. In the present study, BRS measured during daytime increased by 24% after 4 weeks of therapeutic CPAP, indicating that the beneficial effect of treatment on the cardiac sympatho-vagal balance is not limited to the sleep period.…”

Section: Brssupporting

confidence: 59%

CPAP and measures of cardiovascular risk in males with OSAS

Kohler¹,

Pepperell²,

Casadei³

et al. 2008

European Respiratory Journal

175

115

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Obstructive sleep apnoea syndrome (OSAS) has been associated with hypertension, stroke and myocardial ischaemia in epidemiological and observational studies. Continuous positive airway pressure (CPAP) is the treatment of choice for OSAS, but the impact of this intervention on established risk factors for cardiovascular disease remains incompletely understood.A total of 102 males with moderate-to-severe OSAS were randomised to therapeutic (n551) or subtherapeutic (n551) CPAP treatment for 4 weeks to investigate the effects of active treatment on 24-h urinary catecholamine excretion, baroreflex sensitivity (BRS), arterial stiffness (augmentation index) and 24-h ambulatory blood pressure (ABP).After 4 weeks of therapeutic CPAP, significant reductions were seen in urine normetanephrine excretion (from mean¡SD 179.7¡80.1 to 132.7¡46.5 mmol?mol -1 creatinine) and augmentation index (from 14.5¡11.3 to 9.1¡13.8%) compared with the subtherapeutic control group. Furthermore, therapeutic CPAP significantly improved BRS (from 7.1¡3.3 to 8.8¡4.2 ms?mmHg) and reduced mean arterial ABP by 2.6¡5.4 mmHg.In conclusion, treatment of obstructive sleep apnoea with continuous positive airway pressure may lower cardiovascular risk by reducing sympathetic nerve activity, ambulatory blood pressure and arterial stiffness and by increasing sensitivity of the arterial baroreflex.

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Section: Brssupporting

confidence: 59%

CPAP and measures of cardiovascular risk in males with OSAS

Kohler¹,

Pepperell²,

Casadei³

et al. 2008

European Respiratory Journal

175

115

View full text Add to dashboard Cite

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“…During aging, there is impairment of the baroreflex sensitivity (BRS) for control of heart rate (HR) (13, 15, 32), a marker of parasympathetic tone mediated at the level of the solitary tract nucleus (NTS) in the dorsal medulla (2), due to changes in central neuronal and peripheral vascular function. Importantly, baroreflex dysfunction is permissive to chronic sympathetic activation to increase blood pressure and its variability and is an independent risk factor for cardiovascular morbidity and mortality (25,42). The precise mechanisms involved in agerelated baroreflex impairments, however, are not fully understood.…”

mentioning

confidence: 99%

Endogenous leptin contributes to baroreflex suppression within the solitary tract nucleus of aged rats

Arnold

Diz

2014

American Journal of Physiology-Heart and Circulatory Physiology

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Arnold AC, Diz DI. Endogenous leptin contributes to baroreflex suppression within the solitary tract nucleus of aged rats. Am J Physiol Heart Circ Physiol 307: H1539 -H1546, 2014. First published September 26, 2014; doi:10.1152/ajpheart.00282.2014.-The decline in cardiovagal baroreflex function that occurs with aging is accompanied by an increase in circulating leptin levels. Our previous studies showed that exogenous leptin impairs the baroreflex sensitivity for control of heart rate in younger rats, but the contribution of this hormone to baroreflex dysfunction during aging is unknown. Thus we assessed the effect of bilateral leptin microinjection (500 fmol/60 nl) within the solitary tract nucleus (NTS) on the baroreflex sensitivity in older (66 Ϯ 2 wk of age) urethane/chloralose anesthetized SpragueDawley rats with elevated circulating leptin levels. In contrast to the 63% reduction observed in younger rats, leptin did not alter the baroreflex sensitivity for bradycardia evoked by phenylephrine in older rats (0.76 Ϯ 0.19 baseline vs. 0.71 Ϯ 0.15 ms/mmHg after leptin; P ϭ 0.806). We hypothesized that this loss of sensitivity reflected endogenous suppression of the baroreflex by elevated leptin, rather than cardiovascular resistance to the peptide. Indeed, NTS administration of a leptin receptor antagonist (75 pmol/120 nl) improved the baroreflex sensitivity for bradycardia in older rats (0.73 Ϯ 0.13 baseline vs. 1.19 Ϯ 0.26 at 10 min vs. 1.87 Ϯ 0.32 at 60 min vs. 1.22 Ϯ 0.54 ms/mmHg at 120 min; P ϭ 0.002), with no effect in younger rats. There was no effect of the leptin antagonist on the baroreflex sensitivity for tachycardia, responses to cardiac vagal chemosensitive fiber activation, or resting hemodynamics in older rats. These findings suggest that the actions of endogenous leptin within the NTS, either produced locally or derived from the circulation, contribute to baroreflex suppression during aging. autonomic; aging; arterial baroreflex; leptin THE ARTERIAL BARORECEPTOR reflex is critically involved in short-term regulation of blood pressure through modulation of central autonomic pathways that control sympathetic and parasympathetic outflow to peripheral cardiovascular organs. During aging, there is impairment of the baroreflex sensitivity (BRS) for control of heart rate (HR) (13, 15, 32), a marker of parasympathetic tone mediated at the level of the solitary tract nucleus (NTS) in the dorsal medulla (2), due to changes in central neuronal and peripheral vascular function. Importantly, baroreflex dysfunction is permissive to chronic sympathetic activation to increase blood pressure and its variability and is an independent risk factor for cardiovascular morbidity and mortality (25,42). The precise mechanisms involved in agerelated baroreflex impairments, however, are not fully understood. The identification of hormones or other factors that modulate autonomic brainstem regions, such as the NTS, may therefore improve our understanding of the decline in baroreflex function that occurs with aging.Aging is...

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“…HRT is interrelated with spontaneous BRS and it may be used in its place as a new diagnostic method (27). It is proven that HRT also predicts mortality and sudden cardiac death in various cardiac abnormalities (14,(28)(29)(30).…”

Section: Discussionmentioning

confidence: 99%

“…Increased sympathetic and decreased vagal tone can interact with all of the electrophysiological mechanisms underlying arrhythmogenesis. Efferent cardiac autonomic activity is largely under the control of baroreceptor and BRS, which is correlated with cardiac arrhythmias (29,30).…”

Section: Discussionmentioning

confidence: 99%