Attenuated pressor responses to amino acids in the rostral ventrolateral medulla after swimming training in conscious rats

Martins‐Pinge, Marli Cardoso; Becker, Lenice Kappes; Garcia, Martha Regina Luccizano; Zoccal, Daniel Breseguello; Neto, Renata Vasconcelos; Basso, Leonardo Salomão; Souza, Hugo Celso Dutra de; Lopes, Oswaldo Ubrı́aco

doi:10.1016/j.autneu.2005.07.007

Cited by 52 publications

(49 citation statements)

References 30 publications

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“…In support of this hypothesis, we and others have reported physical activitydependent changes within brain regions involved in cardiovascular control (33). These changes include alterations in neuronal firing properties (21), differences in neuronal structure and innervation (19,37), and sensitivity to glutamate microinjections (26,34). Interestingly, exercise training in rabbits with heart failure reduces components of the central renin-angiotensin system and is associated with reductions in elevation plasma ANG II levels (32).…”

Section: Discussionmentioning

confidence: 63%

Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin

Mueller

2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Mueller PJ. Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin. Am J Physiol Regul Integr Comp Physiol 295: R727-R732, 2008. First published May 28, 2008 doi:10.1152/ajpregu.00144.2008.-Physical inactivity is an independent risk factor for cardiovascular disease. Sedentary animals compared to physically active controls exhibit enhanced sympathoexcitatory responses, including arterial baroreflexmediated sympathoexcitation. Hypotension-induced sympathoexcitation is also associated with the release of vasoactive hormones. We hypothesized that sedentary conditions may enhance release of the vasoactive hormones AVP and ANG II. To test this hypothesis, the humoral response to hypotension was examined in conscious rats after 9 -12 wk of sedentary conditions or "normally active" conditions. Normally active conditions were produced by allowing rats access to running wheels in their home cages. Running distance peaked after 4 wk (4.5 Ϯ 0.7 km/day), and the total distance run after 9 wk was 174 Ϯ 23 km (n ϭ 25). Similar levels of hypotension were induced in conscious sedentary or physically active animals with the arterial vasodilator, diazoxide (25 mg/kg iv). Control experiments used a saline injection of equivalent volume. Plasma samples were collected and assayed for plasma AVP concentration and plasma renin activity (PRA). Sedentary conditions significantly enhanced resting and hypotension-induced PRA relative to normal physical activity. In contrast, resting and hypotension-induced AVP levels were not statistically different between groups. These data suggest that baroreflexmediated activation of the renin-angiotensin system, but not AVP secretion, is enhanced by sedentary conditions. We speculate that augmented activation of the renin-angiotensin system may be related to enhanced sympathetic outflow observed in sedentary animals and may contribute to increased risk of cardiovascular disease in the sedentary population. physical activity; physical inactivity; neurohumoral control; angiotensin II

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Section: Discussionmentioning

confidence: 63%

Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin

Mueller

2008

American Journal of Physiology-Regulatory, Integrative and Comp

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“…It has been reported that 4 wk of swim training attenuates the pressor response to microinjection of L-glutamate within RVLM in conscious normotensive rats (34). This finding suggests that RVLM neurons are desensitized after exercise training.…”

Section: Possible Central Mechanisms Mediating Muscle Reflex Improvemmentioning

confidence: 78%

Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats

Mizuno

Iwamoto

Vongpatanasin

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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Mizuno M, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA. Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 309: H762-H770, 2015. First published July 10, 2015; doi:10.1152/ajpheart.00358.2015.-Cardiovascular responses to exercise are exaggerated in hypertension. We previously demonstrated that this heightened cardiovascular response to exercise is mediated by an abnormal skeletal muscle exercise pressor reflex (EPR) with important contributions from its mechanically and chemically sensitive components. Exercise training attenuates exercise pressor reflex function in healthy subjects as well as in heart failure rats. However, whether exercise training has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the EPR overactivity manifest in hypertension is mitigated by exercise training. Changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to muscle contraction, passive muscle stretch, and hindlimb intra-arterial capsaicin administration were examined in untrained normotensive Wistar-Kyoto rats (WKY UT; n ϭ 6), exercise-trained WKY (WKYET; n ϭ 7), untrained spontaneously hypertensive rats (SHR UT; n ϭ 8), and exercise-trained SHR (SHRET; n ϭ 7). Baseline MAP after decerebration was significantly decreased by 3 mo of wheel running in SHR ET (104 Ϯ 9 mmHg) compared with SHR UT (125 Ϯ 10 mmHg). As previously reported, the pressor and renal sympathetic responses to muscle contraction, stretch, and capsaicin administration were significantly higher in SHR UT than WKYUT. Exercise training significantly attenuated the enhanced contraction-induced elevations in MAP (SHR UT: 53 Ϯ 11 mmHg; SHR ET: 19 Ϯ 3 mmHg) and RSNA (SHRUT: 145 Ϯ 32%; SHRET: 57 Ϯ 11%). Training produced similar attenuating effects in SHR during passive stretch and capsaicin administration. These data demonstrate that the abnormally exaggerated EPR function that develops in hypertensive rats is significantly diminished by exercise training. exercise pressor reflex; blood pressure; sympathetic nerve activity; hypertension; exercise training NEW & NOTEWORTHYThe study demonstrates that the exercise pressor reflex overactivity manifest in hypertension is attenuated by dynamic exercise training. Moreover, training normalizes the dysfunction of the mechanically and chemically sensitive components of the reflex. These findings identify a novel mechanism by which exercise training is beneficial in the treatment of hypertension.

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“…In a previous study (26), we investigated the effects of a protocol of chronic exercise on the glutamatergic neurotransmission in the RVLM of conscious rats. At this level of physical training, with baseline bradycardia, the glutamate pressor responses in the RVLM produced attenuated increases in MAP compared to control.…”

Section: Modulation By Brainstem Areasmentioning

confidence: 99%

Cardiovascular and autonomic modulation by the central nervous system after aerobic exercise training

Martins‐Pinge

2011

Braz J Med Biol Res

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The autonomic nervous system plays a key role in maintaining homeostasis under normal and pathological conditions. The sympathetic tone, particularly for the cardiovascular system, is generated by sympathetic discharges originating in specific areas of the brainstem. Aerobic exercise training promotes several cardiovascular adjustments that are influenced by the central areas involved in the output of the autonomic nervous system. In this review, we emphasize the studies that investigate aerobic exercise training protocols to identify the cardiovascular adaptations that may be the result of central nervous system plasticity due to chronic exercise. The focus of our study is on some groups of neurons involved in sympathetic regulation. They include the nucleus tractus solitarii, caudal ventrolateral medulla and the rostral ventrolateral medulla that maintain and regulate the cardiac and vascular autonomic tonus. We also discuss studies that demonstrate the involvement of supramedullary areas in exercise training modulation, with emphasis on the paraventricular nucleus of the hypothalamus, an important area of integration for autonomic and neuroendocrine responses. The results of these studies suggest that the beneficial effects of physical activity may be due, at least in part, to reductions in sympathetic nervous system activity. Conversely, with the recent association of physical inactivity with chronic disease, these data may also suggest that increases in sympathetic nervous system activity contribute to the increased incidence of cardiovascular diseases associated with a sedentary lifestyle.

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Attenuated pressor responses to amino acids in the rostral ventrolateral medulla after swimming training in conscious rats

Cited by 52 publications

References 30 publications

Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin

Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin

Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats

Cardiovascular and autonomic modulation by the central nervous system after aerobic exercise training

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