Malnutrition enhances cardiovascular responses to chemoreflex activation in awake rats

Penitente, Arlete Rita; Fernandes, Luciano; Cardoso, Leonardo Máximo; Silva, Marcelo Eustáquio; Pedrosa, Maria Lúcia; Silva, Antônio Leite; Haibara, Andréa Siqueira; Moraes, Márcio Flávio Dutra; Chianca, Deoclécio A.

doi:10.1016/j.lfs.2007.07.006

Cited by 21 publications

(46 citation statements)

References 33 publications

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“…This is in accordance with previous study from our lab (Martins et al, 2011) which indicate that the low-frequency component of the heart rate variability is increased in malnourished rats. The increased sympathetic tonus was also suggested by Penitente et al (2007), so this may be responsible for the reduction in the barorefl ex gain and range observed in these animals, and therefore for the increased baseline heart rate.…”

Section: Discussionmentioning

confidence: 64%

“…Therefore, these changes in neurotransmitter release and/or receptor affi nity may also be responsible for the impact of malnutrition on the cardiovascular system. Allied to this, rats submitted to protein malnutrition after weaning present increased pressor response to chemorefl ex activation (Penitente et al, 2007), another important cardiovascular reflex. Loss et al (2007) showed that the onset of the sympathoexcitation and parasympathoexcitation eff ects is changed in malnourished rats.…”

Section: Discussionmentioning

confidence: 92%

“…In agreement with this observation, several studies in the literature report that malnutrition, irrespective of the model used, can cause changes in the neurotransmitter concentration in the CNS, in neurotransmitter/receptor affinity (Gotoh et al, 1996;Plagemann et al, 2000;Plagemann et al, 2006;Seidler et al, 1990;Zippel et al, 2003) and in the neuronal population and/or CNS nucleus morphology (Plagemann et al, 2000;Plagemann et al, 2006). These alterations may be responsible for defi cits in memory and learning (Gray, 1989;Gray and Gray, 1989;Hall et al, 1983;Hall, 1983;Plagemann et al, 2000;Plagemann et al, 2006), motor activity (Gallo, 1981;Plagemann et al, 2000;Plagemann et al, 2006), affective behavior (Gallo, 1981;Hall et al, 1983;Hall, 1983), endocrine (Benabe and Martinez-Maldonado, 1993;Plagemann and Harder, 2009;Sawaya et al, 2003) and cardiovascular systems (Loss et al, 2007;Penitente et al, 2007;Tropia et al, 2001) observed in malnourished animals. Therefore, these changes in neurotransmitter release and/or receptor affi nity may also be responsible for the impact of malnutrition on the cardiovascular system.…”

Section: Discussionmentioning

confidence: 99%

“…This lack of modulation of sympathetic activity by the RVLM may explain, in part, the autonomic imbalance observed in previous studies of our group. This autonomic imbalance in turn may contribute to the changes observed in the cardiovascular responses to activation of the barorefl ex (Loss et al, 2007), chemorefl ex (Penitente et al, 2007) and von Bezold-Jarisch refl ex (Bezerra et al, 2011a(Bezerra et al, , 2011b. It is well established in the literature that autonomic imbalance and cardiovascular neural refl ex impairment lead to hypertension and cardiovascular diseases.…”

Section: As Depicted Inmentioning

confidence: 99%

“…Previous studies from our lab have shown that afterweaning malnutrition affects neural mechanisms involved in cardiovascular homeostasis (Bezerra et al, 2011a;Bezerra et al, 2011b;Loss et al, 2007;Martins et al, 2011;Oliveira et al, 2004;Penitente et al, 2007;Tropia et al, 2001). While the exact mechanism remains to be understood, there is evidence indicating that malnutrition can aff ect the release of neurotransmitters and receptor affi nity in several areas of the central nervous system (El et al, 1999;Gotoh et al, 1996;Seidler et al, 1990) The rostral ventrolateral medulla (RVLM) is a bulbar site among the neural pathways of cardiovascular refl exes (e.g., barorefl ex); it contains reticulo-spinal neurons that innervate the pre-ganglionic sympathetic neurons (Ross et al, 1984).…”

Section: Introductionmentioning

confidence: 98%

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Malnutrition affects the pressor response to microinjection of L-glutamate into the RVLM of awake rats

2012

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Post-weaning protein malnutrition is often related to the development of cardiovascular and metabolic diseases in humans, as well to changed content of neurotransmitters in the central nervous system under experimental conditions. The rostral ventrolateral medulla (RVLM) is a bulbar region that contains sympathetic premotor neurons; the excitatory amino acid L-glutamate seems to be the main neurotransmitter at this level. The aim of the present study was to evaluate the possible change in the L-glutamate sensitivity of the RVLM neurons of malnourished animals. Male Fischer rats were divided into two groups: control (n = 15) and malnourished (n = 19). Four days before the experiments, guide cannulas were implanted bilaterally in direction of the RVLM for microinjection of L-glutamate. Twenty-four hours before the experiments, the femoral artery was cannulated for cardiovascular recordings. The results showed that the baseline heart rate increased in malnourished compared to control animals (412.18 ± 16.03 bpm vs. 370.74 ± 9.59 bpm, respectively). Malnourished animals presented a dissimilar concentration-dependent pressor response curve to L-glutamate and an attenuated barorefl ex gain. Our results suggest that post-weaning protein restriction aff ects glutamatergic neurotransmission of the barorefl ex at the RVLM level.

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Section: Discussionmentioning

confidence: 64%

Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: As Depicted Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Malnutrition affects the pressor response to microinjection of L-glutamate into the RVLM of awake rats

2012

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Bezold–Jarisch reflex in sino-aortic denervated malnourished rats

Bezerra

Xavier

Menezes

et al. 2011

Autonomic Neuroscience

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In this study we assessed the role of Bezold-Jarisch reflex (BJR) in the regulation of blood pressure (BP) of malnourished (MN) and control rats (CN) with sino-aortic denervation (SAD). Fischer rats were fed diets containing either 6% (MN) or 15% (CN) protein for 35 days after weaning. These rats underwent sham or SAD and catheterization of femoral artery and vein for BP measurements and drug injection. Phenylbiguanide (PBG 5 μg/kg, i.v.) for activation BJR, produced bradycardia (-317±22 bpm for CN vs. -372±16 bpm for MN) and hypotension (-57±4 mm Hg for CN vs. -54±6 mm Hg for MN. After SAD, MN rats had reduced hypotensive (-37±7 mm Hg for MN vs. -82±6 mm Hg for CN) and bradycardic (-124±17 for MN vs. -414±20 bpm CN) responses to BJR activation. To evaluate the contribution of the parasympathetic component due to BJR for the fall in BP, methyl atropine bromide, was given between two injections of PBG (5 μg/kg) separated by 10 min each other. Both bradycardic (-216±21 bpm before and -4±3 bpm after for CN -226±43 bpm before and -9±20 bpm after for MN) and hypotensive (-42±4 mm Hg before and -6±1 mm Hg after for CN -33±9 mm Hg before and -5±2 mm Hg after for MN) responses were abolished in CN and MN groups. These data indicate that dietary protein malnutrition changes the relation between baroreflex and BJR required for maintenance of the BP during malnourishment.

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Chemoreflex control of the cardiovascular system remains altered after recovery from low protein diet early in life

Sá

Borges

Chianca

et al. 2014

Autonomic Neuroscience

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Malnutrition enhances cardiovascular responses to chemoreflex activation in awake rats

Cited by 21 publications

References 33 publications

Malnutrition affects the pressor response to microinjection of L-glutamate into the RVLM of awake rats

Malnutrition affects the pressor response to microinjection of L-glutamate into the RVLM of awake rats

Bezold–Jarisch reflex in sino-aortic denervated malnourished rats

Chemoreflex control of the cardiovascular system remains altered after recovery from low protein diet early in life

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