Progressive attenuation of the carotid baroreflex control of blood pressure and heart rate during exercise

Staessen, Jan A.; Fiocchi, R; Fagard, Robert; Hespel, Peter; Améry, A

doi:10.1016/0002-8703(87)90787-3

Cited by 21 publications

(16 citation statements)

References 17 publications

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“…The bradycardia evoked by ADN stimulation was modulated by voluntary static exercise, whereas the evoked depressor response was not significantly affected by the exercise, in this study. Similarly, isometric handgrip exercise reduced the baroreflex bradycardia caused by an increase in carotid sinus transmural pressure but did not affect the depressor response in humans (18,47). Static exercise is, therefore, considered to have differential influences on the cardiac and vasomotor components of the aortic and carotid sinus baroreflexes.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the response in R-R interval or HR to a change in carotid sinus transmural pressure was blunted during dynamic or static exercise in humans (18,19,47) and baboons (5), although Bevegård and Shephard (2) reported that a reflex decrease in HR in response to neck suction was similar during rest and exercise. On the other hand, the responses in AP to neck pressure and suction were less affected or preserved during exercise (2,8,18,47). These results suggest that the sensitivity of the cardiac component of the carotid and aortic baroreflexes is attenuated around the operating point during exercise.…”

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confidence: 99%

“…When baroreflex sensitivity was assessed as a ratio of the change in R-R interval or HR in response to an alteration in AP, it was reduced during dynamic or static exercise in humans (3,14) and dogs (25). In addition, the response in R-R interval or HR to a change in carotid sinus transmural pressure was blunted during dynamic or static exercise in humans (18,19,47) and baboons (5), although Bevegård and Shephard (2) reported that a reflex decrease in HR in response to neck suction was similar during rest and exercise. On the other hand, the responses in AP to neck pressure and suction were less affected or preserved during exercise (2,8,18,47).…”

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Central command blunts the baroreflex bradycardia to aortic nerve stimulation at the onset of voluntary static exercise in cats

Komine

Matsukawa

Tsuchimochi

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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Komine, Hidehiko, Kanji Matsukawa, Hirotsugu Tsuchimochi, and Jun Murata. Central command blunts the baroreflex bradycardia to aortic nerve stimulation at the onset of voluntary static exercise in cats. Am J Physiol Heart Circ Physiol 285: H516-H526, 2003. First published May 1, 2003 10.1152/ajpheart.00013.2003.-To examine whether the central characteristics of the aortic baroreflex alter from moment to moment during static exercise, we identified the dynamic changes in the sizes of the bradycardia and depressor response evoked by stimulation of the aortic depressor nerve (ADN). Three conscious cats were trained to voluntarily extend the right forelimb and press a bar for 31 Ϯ 1 s with a peak force of 337 Ϯ 22 g while maintaining a sitting posture. The ADN stimulation-induced bradycardia was attenuated at the initial period of exercise (up to 8 s from the exercise onset) to 62 Ϯ 5% of the preexercise bradycardia and remained blunted until the end of exercise. The most blunted bradycardia was observed immediately before or when the forelimb was extended before force development. The baroreflex-induced bradycardia was suppressed again at cessation of exercise when the forelimb was retracted and recovered within a few seconds. In contrast, static exercise did not affect the ADN stimulation-induced depressor response. The ADN stimulation-induced bradycardia was also blunted at the beginning of naturally occurring body movement such as spontaneous postural change or grooming behavior. Thus it is likely that the central characteristics of the aortic baroreflex dynamically change from moment to moment during voluntary static exercise and during natural body movement and that particularly a central inhibition of the cardiac component of the aortic baroreflex is induced by central command at the onset of static exercise, whereas the central property of the vasomotor component of the baroreflex is preserved.aortic depressor nerve; aortic baroreceptors; baroreflex sensitivity; baroreflex depressor response; central modulation of the arterial baroreflex ARTERIAL BLOOD PRESSURE (AP) is sensed by arterial baroreceptors in the carotid sinus and aortic arch regions, whose activities transmit the beat-to-beat changes in AP to the central nervous system and evoke the baroreflex responses of autonomic efferent nerve activities to the heart and blood vessels. For example, if AP increases during resting, arterial baroreceptors are stimulated in proportion to the rise in AP, which elicits reflex bradycardia and depressor response and thereby restores AP to the control level. However, it is well known that heart rate (HR) and AP increase simultaneously during static or dynamic exercise in humans and conscious animals, indicating that arterial baroreflex function is modulated by exercise.The effect of exercise on the arterial baroreflexes has been extensively studied in humans and animals. When baroreflex sensitivity was assessed as a ratio of the change in R-R interval or HR in response to an alteration in AP, it was reduced during d...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Central command blunts the baroreflex bradycardia to aortic nerve stimulation at the onset of voluntary static exercise in cats

Komine

Matsukawa

Tsuchimochi

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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“…For example, if arterial baroreceptors are stimulated in proportion to a rise in AP, reflex bradycardia is elicited to restore AP to the control level. However, because heart rate (HR) and AP increase simultaneously during static and dynamic exercise in humans and conscious animals, it has been thought that arterial baroreflex function is modulated during exercise (1,2,14,21,36). The stimulus-response curve of the arterial baroreflex has been studied in the steady state of exercise.…”

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confidence: 99%

Central command blunts sensitivity of arterial baroreceptor-heart rate reflex at onset of voluntary static exercise

Matsukawa

Komine

Nakamoto

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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Matsukawa, Kanji, Hidehiko Komine, Tomoko Nakamoto, and Jun Murata. Central command blunts sensitivity of arterial baroreceptor-heart rate reflex at onset of voluntary static exercise. Am J Physiol Heart Circ Physiol 290: H200 -H208, 2006. First published August 19, 2005 doi:10.1152/ajpheart.00013.2005.-We have reported that baroreflex bradycardia by stimulation of the aortic depressor nerve is blunted at the onset of voluntary static exercise in conscious cats. Central command may contribute to the blunted bradycardia, because the most blunted bradycardia occurs immediately before exercise or when a forelimb is extended before force development. However, it remained unknown whether the blunted bradycardia is due to either reduced sensitivity of the baroreflex stimulus-response curve or resetting of the curve toward a higher blood pressure. To determine this, we examined the stimulus-response relationship between systolic (SAP) or mean arterial pressure (MAP) and heart rate (HR) at the onset of and during the later period of static exercise in seven cats (n ϭ 348 trials) by changing arterial pressure with infusion of nitroprusside and phenylephrine or norepinephrine. The slope of the MAP-HR curve decreased at the onset of exercise to 48% of the preexercise value (2.9 Ϯ 0.4 beats ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ); the slope of the SAP-HR curve decreased to 59%. The threshold blood pressures of the stimulus-response curves, at which HR started to fall due to arterial baroreflex, were not affected. In contrast, the slopes of the stimulus-response curves during the later period of exercise returned near the preexercise levels, whereas the threshold blood pressures elevated 6 -8 mmHg. The maximal plateau level of HR was not different before and during static exercise, denying an upward shift of the baroreflex stimulus-response curves. Thus central command is likely to attenuate sensitivity of the cardiac component of arterial baroreflex at the onset of voluntary static exercise without shifting the stimulus-response curve.gain; resetting; exercise pressor reflex; conscious cat ARTERIAL BLOOD PRESSURE (AP) is sensed by arterial baroreceptors in the carotid sinus and aortic arch regions, whose activities transmit the beat-to-beat changes in AP to the central nervous system and promote the baroreflex responses of autonomic efferent nerve activities to the heart and blood vessels. For example, if arterial baroreceptors are stimulated in proportion to a rise in AP, reflex bradycardia is elicited to restore AP to the control level. However, because heart rate (HR) and AP increase simultaneously during static and dynamic exercise in humans and conscious animals, it has been thought that arterial baroreflex function is modulated during exercise (1, 2, 14, 21, 36). The stimulus-response curve of the arterial baroreflex has been studied in the steady state of exercise. Melcher and Donald (23), when studying carotid baroreflex function with the isolated carotid sinuses in conscious dogs, found that the stimulus-response curve was displaced...

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“…[1][2] The baroreflex response is typically initiated by changes in blood pressure or volume that stimulate arterial baroreceptors located in the carotid sinus and aortic arch. 1 The impulses triggered by arterial baroreceptors are propagated through the glossopharyngeal and vagus nerves to the nucleus tractus solitarii of the medulla, resulting in inhibition of the sympathetic system and activation of the parasympathetic system.…”

Section: Introductionmentioning

confidence: 99%

Altered nitroxidergic and NMDA receptor-mediated modulation of baroreflex-mediated heart rate in obese Zucker rats

et al. 2010

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Arterial baroreflex, an important physiological regulatory system for buffering systemic blood pressure, is impaired in obesity. This study investigated whether the blunted baroreflex function in obesity is attributed to the altered nitroxidergic or N-methyl-Daspartate (NMDA) mechanism. Baroreflex bradycardia responses, blood pressure and heart rate in 30 lean and 30 obese anesthetized Zucker rats (8-12 weeks of age) were assessed after injecting phenylephrine with intravenous preadministration of saline (control), dextromethorphan (DXM, NMDA receptor antagonist, 10 mg kg À1 ) or N(G)-nitro-L-arginine methyl ester (L-NAME, nitric oxide synthase inhibitor, 100 mg kg À1 ). Compared with lean rats (À2.00 ± 0.29 b.p.m. mm Hg À1 ), the baroreflex sensitivity (BRS) in obese rats (-0.43±0.05 b.p.m. mm Hg À1 ) was significantly blunted. The BRS was significantly suppressed by DXM in lean rats but not in obese rats. After administration of L-NAME, BRS was significantly suppressed in lean Zucker rats but not in obese Zucker rats. The normal BRS was significantly suppressed in lean rats after administration of both DXM and L-NAME, and the blunted BRS in obesity was significantly blocked to nearly no BRS after administration of both DXM and L-NAME. This study suggests that BRS is blunted in obese rats and that blunted baroreflex is, at least in part, attributed to altered nitroxidergic or NMDA receptor-mediated modulation.

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Progressive attenuation of the carotid baroreflex control of blood pressure and heart rate during exercise

Cited by 21 publications

References 17 publications

Central command blunts the baroreflex bradycardia to aortic nerve stimulation at the onset of voluntary static exercise in cats

Central command blunts the baroreflex bradycardia to aortic nerve stimulation at the onset of voluntary static exercise in cats

Central command blunts sensitivity of arterial baroreceptor-heart rate reflex at onset of voluntary static exercise

Altered nitroxidergic and NMDA receptor-mediated modulation of baroreflex-mediated heart rate in obese Zucker rats

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