Abnormal Neurovascular Control During Sympathoexcitation in Obesity

Kuniyoshi, Fatima H. Sert; Tombetta, I C; Batalha, L. T.; Rondon, M Upb; Laterza, Mateus Camaroti; Gowdak, Mmg; Barretto, Anjali; Halpern, Alfredo; Villares, S. M. F.; Lima, Emerson Quintino de; Negräo, Carlos Eduardo

doi:10.1097/00004872-200402001-00066

Cited by 31 publications

(45 citation statements)

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“…13 Our finding of invariant cardiovascular responses to air-jet stress between HFD and control animals suggests that, early in the development of obesity-related hypertension, there is no potentiation of stress pathways. In fact, we observed progressive diminution of blood pressure, HR, and RSNA responses to stress as the HFD diet progressed.…”

Section: Armitage Et Al Sympathetic Drive In Obesity-related Hypertenmentioning

confidence: 79%

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Rapid Onset of Renal Sympathetic Nerve Activation in Rabbits Fed a High-Fat Diet

et al. 2012

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Abstract-Hypertension and elevated sympathetic drive result from consumption of a high-calorie diet and deposition of abdominal fat, but the etiology and temporal characteristics are unknown. Rabbits instrumented for telemetric recording of arterial pressure and renal sympathetic nerve activity (RSNA) were fed a high-fat diet for 3 weeks then control diet for 1 week or control diet for 4 weeks. Baroreflexes and responses to air-jet stress and hypoxia were determined weekly. After 1 week of high-fat diet, caloric intake increased by 62%, accompanied by elevated body weight, blood glucose, plasma insulin, and leptin (8%, 14%, 134%, and 252%, respectively). Mean arterial pressure, heart rate, and RSNA also increased after 1 week (6%, 11%, and 57%, respectively). Whereas mean arterial pressure and body weight continued to rise over 3 weeks of high-fat diet, heart rate and RSNA did not change further. The RSNA baroreflex was attenuated from the first week of the diet. Excitatory responses to air-jet stress diminished over 3 weeks of high-fat diet, but responses to hypoxia were invariant. Resumption of a normal diet returned glucose, insulin, leptin, and heart rate to control levels, but body weight, mean arterial pressure, and RSNA remained elevated. In conclusion, elevated sympathetic drive and impaired baroreflex function, which occur within 1 week of consumption of a high-fat, high-calorie diet, appear integral to the rapid development of obesity-related hypertension. Increased plasma leptin and insulin may contribute to the initiation of hypertension but are not required for maintenance of mean arterial pressure, which likely lies in alterations in the response of neurons in the hypothalamus. Key Words: sympathetic nervous system Ⅲ obesity Ⅲ rabbits Ⅲ blood pressure Ⅲ heart rate O besity represents a significant risk for cardiovascular disease because of the relationship between excess body fat and hypertension. It is estimated that obesity contributes to hypertension in Ͼ60% of men and women entering the Framingham study.1 The mechanisms underlying this relationship are multifactorial, and for some time there was controversy as to whether the sympathetic nervous system was activated or inhibited in obesity-related hypertension. Bray 2 proposed that obesity was a result of low thermogenic activity secondary to low sympathetic activity, and certainly data from heart rate (HR) variability studies supported this hypothesis. Young and Landsberg 3 hypothesized that sympathetic outflow is increased in obesity to facilitate energy wastage by thermogenesis and to maintain body weight homeostasis, with elevated renal sympathetic activation and hypertension the sequelae. It is now clear that norepinephrine spillover to renal and skeletal muscle beds is increased in obese humans, 4 and microneurographic data indicate that skeletal muscle sympathetic nerve activity is greater in overweight humans, 5 consistent with the observation that sympathetic vasomotor activity in skeletal muscle is elevated in established obesity. 6,7 ...

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Section: Armitage Et Al Sympathetic Drive In Obesity-related Hypertenmentioning

confidence: 79%

“…Obesity-related hypertension is frequently associated with obstructive sleep apnea in which intermittent episodes of hypoxia produce an ongoing elevation in sympathetic nerve activity, even when the hypoxia is not present. 11,12 Moreover, obese subjects have exaggerated neural responses to stressful stimuli, 13 as well as impaired baroreflexes.…”

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confidence: 99%

Rapid Onset of Renal Sympathetic Nerve Activation in Rabbits Fed a High-Fat Diet

et al. 2012

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“…Muscle sympathetic nerve activity is increased during exercise and mental stress in obese individuals. 3,4 In contrast, the reflexively mediated increase in muscle blood flow during these physiological maneuvers is attenuated in obese individuals. During the cold pressor test, muscle sympathetic nerve activity and muscle vascular resistance are increased in obese women compared with lean women.…”

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confidence: 99%

Diet and Exercise Training Restore Blood Pressure and Vasodilatory Responses During Physiological Maneuvers in Obese Children

et al. 2005

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Background-The effects of diet and diet plus exercise training on muscle vasodilatation during physiological maneuvers in obese children are unknown. We tested the hypothesis that (1) blood pressure (BP) and forearm vascular conductance (FVC) responses during handgrip exercise and mental stress would be altered in obese children and (2) diet plus exercise training would restore BP and FVC responses during exercise and mental stress in obese children. Methods and Results-Thirty-nine obese children (aged 10Ϯ0.2 years) were randomly divided into 2 groups: diet plus exercise training (nϭ21; body mass index [BMI]ϭ28Ϯ0.5 kg/m 2 ) and diet (nϭ18; BMIϭ30Ϯ0.4 kg/m 2 ). Ten age-matched lean control children (BMIϭ17Ϯ0.5 kg/m 2 ) were also studied. Forearm blood flow was measured by venous occlusion plethysmography. BP was monitored noninvasively. Handgrip exercise was performed at 30% maximal voluntary contraction for 3 minutes. Stroop color word test was performed for 4 minutes. Baseline BP was significantly higher and FVC was significantly lower in obese children. During exercise and mental stress, BP responses were significantly higher and FVC responses were significantly lower in obese children. Diet and diet plus exercise training significantly reduced body weight. Diet and diet plus exercise training significantly decreased BP levels during exercise and mental stress. Diet plus exercise training, in contrast to diet alone, significantly increased FVC responses during exercise

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“…These changes may lead to increased levels of blood pressure and decreased blood flow to muscles. During sympathoexcitatory maneuvers, such as isometric exercise, cold pressor test or mental stress, the vasodilator reflex that should increase muscle blood flow is attenuated in obesity 5,9 . Furthermore, these changes are already present in obese children and it has been shown that non-pharmacological therapy based on diet and exercise can restore the physiological responses of blood pressure and vasodilation during physiological maneuvers of mental stress and isometric exercise 10,11 .…”

Section: Introductionmentioning

confidence: 99%

Vitamina C restaura pressão arterial e a resposta vasodilatadora no antebraço em crianças obesas

Fernandes¹,

Lira²,

Borba³

et al. 2011

Arq. Bras. Cardiol.

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Abnormal Neurovascular Control During Sympathoexcitation in Obesity

Cited by 31 publications

References 0 publications

Rapid Onset of Renal Sympathetic Nerve Activation in Rabbits Fed a High-Fat Diet

Rapid Onset of Renal Sympathetic Nerve Activation in Rabbits Fed a High-Fat Diet

Diet and Exercise Training Restore Blood Pressure and Vasodilatory Responses During Physiological Maneuvers in Obese Children

Vitamina C restaura pressão arterial e a resposta vasodilatadora no antebraço em crianças obesas

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