Cardiopulmonary reflexes and arterial pressure during rest and exercise in dogs

Walgenbach, S. C.; Donald, David E.

doi:10.1152/ajpheart.1983.244.3.h362

Cited by 19 publications

(15 citation statements)

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“…Moreover, the ABR, together with central command and the exercise pressor reflex play an essential role in evoking appropriate neural cardiovascular responses to exercise. Indeed, sinoaortic denervation and reductions in ABR control have been shown to lead to exaggerated elevations in BP upon exercise (6,56,57). Thus appropriate ABR resetting and function are requisite for normal BP responses to dynamic exercise (14,26,46,47).…”

mentioning

confidence: 99%

Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans

Kim

Deo²,

Fisher

et al. 2012

Journal of Applied Physiology

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Kim A, Deo SH, Fisher JP, Fadel PJ. Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans. J Appl Physiol 112: 1361-1371, 2012. First published January 19, 2012 doi:10.1152/japplphysiol.01308.2011.-To date, no studies have examined whether there are either sex-or ovarian hormone-related alterations in arterial baroreflex resetting and function during dynamic exercise. Thus we studied 16 young men and 18 young women at rest and during leg cycling at 50% heart rate (HR) reserve. In addition, 10 women were studied at three different phases of the menstrual cycle. Five-second pulses of neck pressure (NP) and neck suction (NS) from ϩ40 to Ϫ80 Torr were applied to determine full carotid baroreflex (CBR) stimulus response curves. An upward and rightward resetting of the CBR function curve was observed during exercise in all groups with a similar magnitude of CBR resetting for mean arterial pressure (MAP) and HR between sexes (P Ͼ 0.05) and at different phases of the menstrual cycle (P Ͼ 0.05). For CBR control of MAP, women exhibited augmented pressor responses to NP at rest and exercise during mid-luteal compared with early and late follicular phases. For CBR control of HR, there was a greater bradycardic response to NS in women across all menstrual cycle phases with the operating point (OP) located further away from centering point (CP) on the CBR-HR curve during rest (OP-CP; in mmHg: Ϫ13 Ϯ 3 women vs. Ϫ3 Ϯ 3 men; P Ͻ 0.05) and exercise (in mmHg: Ϫ31 Ϯ 2 women vs. Ϫ15 Ϯ 3 men; P Ͻ 0.05). Collectively, these findings suggest that sex and fluctuations in ovarian hormones do not influence exercise resetting of the baroreflex. However, women exhibited greater CBR control of HR during exercise, specifically against acute hypertension, an effect that was present throughout the menstrual cycle. arterial baroreceptors; blood pressure; gender; estradiol; progesterone; menstrual cycle THE ARTERIAL BAROREFLEX (ABR) plays an important role in beat-to-beat control of blood pressure (BP) via modulating autonomic neural activity to the heart and vasculature (46, 47). The ABR is reset during dynamic exercise partly due to the actions and interactions of two neural mechanisms, namely central command (feedforward signals from higher brain centers) and the exercise pressor reflex (feedback signals from contracting skeletal muscles) (14,19,20,32,46,47). Moreover, the ABR, together with central command and the exercise pressor reflex play an essential role in evoking appropriate neural cardiovascular responses to exercise. Indeed, sinoaortic denervation and reductions in ABR control have been shown to lead to exaggerated elevations in BP upon exercise (6,56,57). Thus appropriate ABR resetting and function are requisite for normal BP responses to dynamic exercise (14,26,46,47).Young men tend to exhibit greater pressor responses to exercise compared with age-matched women (7,12,29,38); however, the reason for these differences remains unclear. Interestingly, studies have shown tha...

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confidence: 99%

Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans

Kim

Deo²,

Fisher

et al. 2012

Journal of Applied Physiology

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“…First, Thoren 39 suggests that the slowly reacting cardiopulmonary receptors seem to be relatively insensitive to the mbment-to-moment changes in blood pressure seen after baroreceptor denervation. Second, Walgenbach and Donald 36 recently showed that cardiopulmonary deafferentation did not affect the lability of the arterial pressure in dogs, in either the presence or absence of functioning arterial baroreceptor reflexes. Therefore, it is doubtful that concomitant destruction of the baroreceptor and cardiopulmonary reflexes contributed markedly to the differences in the lability of arterial pressure of the SAD and NTS groups.…”

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confidence: 99%

“…3839 Kezdi et al 38 have shown increased C-fiber activity from cardiopulmonary receptors after SAD in dogs and suggest this may be sufficient to return pressure to normal or near normal levels. However, Walgenbach and Donald 36 found that, although cardiopulmonary reflexes do exert tonic vasomotor inhibition, this is insufficient to maintain pressure near normal levels in the absence of the arterial baroreceptor reflexes. Furthermore, if damage to the cardiopulmonary reflexes accounted for the mild hypertension in some rats after SAD, then the arterial pressure of all rats with NTS lesions should be similarly elevated, since vagal afferents project densely to the area of the NTS that is consistently destroyed by the lesions.…”

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Comparison of 1-hour and 24-hour blood pressure recordings in central or peripheral baroreceptor-denervated rats.

Buchholz¹,

Hubbard²,

Nathan³

1986

Hypertension

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SUMMARY We compared the mean arterial pressure and heart rate activity of conscious, unrestrained rats during 1-hour and 24-hour continuous recording sessions, 3 to 4 weeks after either sinoaortic denervation, placement of electrolytic lesions in the nucleus tractus solitarii, or sham operations. Sinoaortic denervation and nucleus tractus solitarii lesions both eliminated the reflex bradycardia to a phenylephrine-induced pressor response. No difference was found in the average level and lability of the mean arterial pressure between 1-hour and 24-hour recordings for any group. No elevation in the average mean arterial pressure of rats with nucleus tractus solitarii lesions was observed, although a mild hypertension was noted in half the sinoaortic-denervated rats, while the other half were normotensive. Group differences were not found for heart rate or heart rate variability; however, 24-hour recordings yielded significantly higher values than 1-hour recordings for all groups. Both medullary lesions and sinoaortic denervation significantly increased the lability of the mean arterial pressure, but the magnitude of the increase was significantly greater in the rats with lesions. The lability of the mean arterial pressure in sinoaortic-denervated rats depended largely on movement-related depressor responses that produced a negative skew in the frequency distribution of their mean arterial pressure. Rats with nucleus tractus solitarii lesions exhibited both pressor and depressor responses that resulted in pressure distributions that had a slight positive skew similar to that displayed by control rats. It is concluded that short-term continuous recordings of mean arterial pressure and heart rate accurately estimate the altered cardiovascular activity of baroreceptordenervated rats. T HE cardiovascular response to sinoaortic desurement, the duration of measurement, and the envinervation (SAD) has been studied in rats, ronment in which the arterial pressure was recordcats, rabbits, and dogs.

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“…In the 1980s, David Donal's group at the Mayo Clinic performed a series of investigations using treadmill exercising canines with and without surgically isolated carotid sinus in combination with or without vagotomy (20,64,109,110). The major finding of these studies were that 1) the carotid-HR reflex was reset to a higher OP pressure in association with the increasing exercise intensities and 2) vagal afferent neural information from cardiopulmonary baroreceptors was important for establishing the resetting of the OP pressure.…”

Section: Arterial Baroreflexmentioning

confidence: 99%

“…The current model of circulatory control during exercise holds that it is governed by two main neural mechanisms: 1) the central command (CC), a feedforward control mechanism that sets the basic pattern of motor activity to skeletal muscles and drives cardiorespiratory activation (22,33,62,70), and 2) the feedback control mechanisms driven by intrinsic/extrinsic receptors from cardiovascular areas and receptors within the active muscles (57,71,95,109).…”

mentioning

confidence: 99%

Neural control of circulation and exercise: a translational approach disclosing interactions between central command, arterial baroreflex, and muscle metaboreflex

Michelini

O’Leary

Raven

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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Michelini LC, O'Leary DS, Raven PB, Nobrega AC. Neural control of circulation and exercise: a translational approach disclosing interactions between central command, arterial baroreflex, and muscle metaboreflex*. Am J Physiol Heart Circ Physiol 309: H381-H392, 2015. First published May 29, 2015; doi:10.1152/ajpheart.00077.2015.-The last 100 years witnessed a rapid and progressive development of the body of knowledge concerning the neural control of the cardiovascular system in health and disease. The understanding of the complexity and the relevance of the neuroregulatory system continues to evolve and as a result raises new questions. The purpose of this review is to articulate results from studies involving experimental models in animals as well as in humans concerning the interaction between the neural mechanisms mediating the hemodynamic responses during exercise. The review describes the arterial baroreflex, the pivotal mechanism controlling mean arterial blood pressure and its fluctuations along with the two main activation mechanisms to exercise: central command (parallel activation of central somatomotor and autonomic descending pathways) and the muscle metaboreflex, the metabolic component of exercise pressor reflex (feedback from ergoreceptors within contracting skeletal muscles). In addition, the role of the cardiopulmonary baroreceptors in modulating the resetting of arterial baroreflex is identified, and the mechanisms in the central nervous system involved with the resetting of baroreflex function during dynamic exercise are also described. Approaching a very relevant clinical condition, the review also presents the concept that the impaired arterial baroreflex function is an integral component of the metaboreflex-mediated exaggerated sympathetic tone in subjects with heart failure. This increased sympathetic activity has a major role in causing the depressed ventricular function observed during submaximal dynamic exercise in these patients. The potential contribution of a metaboreflex arising from respiratory muscles is also considered. autonomic; baroreflex; central command; exercise; metaboreflex THIS ARTICLE is part of a collection on 1st Pan American Congress of Physiological Sciences: Physiology Without Borders. Other articles appearing in this collection, as well as a full archive of all collections, can be found online at http://ajpheart.physiology.org/.A wide range of complex but routine behaviors such as feeding, shivering, locomotion, aggressive/defensive, and sexual behaviors triggers concomitant activation of somatomotor and autonomic outflows (47). Dynamic exercise is a complex physiological challenge involving highly coordinated activity of skeletal muscles, rapid and immediate increases in respiratory function, heart rate (HR), stroke volume and cardiac output associated with changes in regional vascular resistance, and redistribution of systemic blood flow that cause a slight increase in mean blood pressure (108). The increased blood flow to active muscles provides the necessary o...

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Cardiopulmonary reflexes and arterial pressure during rest and exercise in dogs

Cited by 19 publications

References 0 publications

Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans

Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans

Comparison of 1-hour and 24-hour blood pressure recordings in central or peripheral baroreceptor-denervated rats.

Neural control of circulation and exercise: a translational approach disclosing interactions between central command, arterial baroreflex, and muscle metaboreflex

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