Baroreflex dysfunction in rats submitted to protein restriction

Loss, Igor de Oliveira; Fernandes, Luciano; Martins, Carlito D'Angelo Drumond; Cardoso, Leonardo Máximo; Silva, Marcelo E.; Dias-da-Silva, V J; Moraes, Márcio Flávio Dutra; Chianca, Deoclécio A.

doi:10.1016/j.lfs.2007.08.005

Cited by 25 publications

(30 citation statements)

References 41 publications

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“…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%

“…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. These observations strengthen the hypothesis of an altered autonomic modulation in animals submitted to malnutrition.…”

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: 99%

Section: Discussionmentioning

confidence: 99%

Section: As Depicted Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

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

2012

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“…After documenting their baseline values, the PE (Sigma-USA) was injected in both groups intravenously in doses of 0.25, 0.5, 1, 2, 5, 8, and 10 µg/kg, respectively (Nijsen et al 2001;Loss Ide et al 2007;Cannesson et al 2012;Guimaraes et al 2012) and the HR and blood pressure (BP) were recorded. Peak of hemodynamic changes was recorded for assessment of response to PE.…”

Section: Measurement Of Cardiovascular System Response To Pementioning

confidence: 99%

Hemodynamic properties and arterial structure in male rat offspring with fetal hypothyroidism

Ghanbari

Bagheripuor²,

Piryaei³

et al. 2016

gpb

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Abstract. Thyroid hormones (THs) play a crucial role in the development of different systems during fetal life; fetal hypothyroidism (FH) is associated with reduced cardiac function and dimensions in neonates. The aim of this study is to determine whether TH deficiency during fetal life is associated with arterial structural and hemodynamic changes during adulthood. Hypothyroidism was induced by adding 0.025% 6-propyl-2-thiouracil in drinking water throughout pregnancy, while controls consumed only tap water. Hemodynamic parameters, cross-sectional area, intima-media thickness (IMT), and density of nuclei of smooth muscle cells and endothelial cells (ECs) in the aorta and mesenteric arteries were measured. Compared to controls, in the FH group, baseline systolic blood pressure (105.7 ± 3.1 vs. 87.9 ± 3.3 mm Hg, p < 0.01), diastolic blood pressure (64.4 ± 1.7 vs. 53.2 ± 2.1 mm Hg, p < 0.05), and mean arterial pressure (80.9 ± 2.1 vs. 67.1 ± 2.1 mm Hg, p < 0.01) were significantly lower. In addition, in the FH group, intensity and latency of response to phenylephrine were significantly lower and longer, respectively, as were the IMT and density of ECs in the aorta and superior mesenteric arteries. In conclusion, this study showed that TH deficiency during fetal life can have long-lasting functional and histological effects, which can compromise cardiovascular function during adulthood.

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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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Baroreflex dysfunction in rats submitted to protein restriction

Cited by 25 publications

References 41 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

Hemodynamic properties and arterial structure in male rat offspring with fetal hypothyroidism

Bezold–Jarisch reflex in sino-aortic denervated malnourished rats

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