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Stress alone or associated with ethanol induces prostanoid release in rat aorta via alpha2-Adrenoceptor.

Baptista Rde F, Taipeiro Ede F, Queiroz RH, Chies AB, Cordellini S - Arq. Bras. Cardiol. (2014)

Bottom Line: EC50 and maximum response (n=8-12) were compared using two-way ANOVA/Bonferroni method.Meanwhile, ethanol consumption did not alter the reactivity to noradrenaline.This effect is dependent upon the vascular endothelium and involves the release of vasoconstrictor prostanoids via stimulation of endothelial alpha-2 adrenoceptors.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, São Paulo, SP, Brasil.

ABSTRACT

Background: Stress and ethanol are both, independently, important cardiovascular risk factors.

Objective: To evaluate the cardiovascular risk of ethanol consumption and stress exposure, isolated and in association, in male adult rats.

Methods: Rats were separated into 4 groups: Control, ethanol (20% in drinking water for 6 weeks), stress (immobilization 1h day/5 days a week for 6 weeks) and stress/ethanol. Concentration-responses curves to noradrenaline - in the absence and presence of yohimbine, L-NAME or indomethacin - or to phenylephrine were determined in thoracic aortas with and without endothelium. EC50 and maximum response (n=8-12) were compared using two-way ANOVA/Bonferroni method.

Results: Either stress or stress in association with ethanol consumption increased the noradrenaline maximum responses in intact aortas. This hyper-reactivity was eliminated by endothelium removal or by the presence of either indomethacin or yohimbine, but was not altered by the presence of L-NAME. Meanwhile, ethanol consumption did not alter the reactivity to noradrenaline. The phenylephrine responses in aortas both with and without endothelium also remained unaffected regardless of protocol.

Conclusion: Chronic stress increased rat aortic responses to noradrenaline. This effect is dependent upon the vascular endothelium and involves the release of vasoconstrictor prostanoids via stimulation of endothelial alpha-2 adrenoceptors. Moreover, chronic ethanol consumption appeared to neither influence noradrenaline responses in rat thoracic aorta, nor did it modify the increase of such responses observed as a consequence of stress exposure.

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Concentration-response curves to phenylephrine obtained from rings of thoracicaorta with and without endothelium taken from animals exposed to ethanolconsumption and/or stress. Values are expressed as means ± SEM. The numberof independent determinations was 8-10.
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f07: Concentration-response curves to phenylephrine obtained from rings of thoracicaorta with and without endothelium taken from animals exposed to ethanolconsumption and/or stress. Values are expressed as means ± SEM. The numberof independent determinations was 8-10.

Mentions: The removal of the endothelium increased the sensitivity to noradrenaline in relation tothe respective aorta with intact endothelium (Table1). Moreover, the removal of the endothelium eliminated the aortichyper-reactivity to noradrenaline observed in stress and stress/ethanol groups (Figure 2A). None of the protocols altered thereactivity to noradrenaline in denuded aortas (Figures2B, 2C and 2D),nor did they affect the reactivity to phenylephrine (Figures 3A and 3B) in intact or denudedaortas. Similar phenylephrine EC50 were also observed among the groups (Table 2).


Stress alone or associated with ethanol induces prostanoid release in rat aorta via alpha2-Adrenoceptor.

Baptista Rde F, Taipeiro Ede F, Queiroz RH, Chies AB, Cordellini S - Arq. Bras. Cardiol. (2014)

Concentration-response curves to phenylephrine obtained from rings of thoracicaorta with and without endothelium taken from animals exposed to ethanolconsumption and/or stress. Values are expressed as means ± SEM. The numberof independent determinations was 8-10.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3987321&req=5

f07: Concentration-response curves to phenylephrine obtained from rings of thoracicaorta with and without endothelium taken from animals exposed to ethanolconsumption and/or stress. Values are expressed as means ± SEM. The numberof independent determinations was 8-10.
Mentions: The removal of the endothelium increased the sensitivity to noradrenaline in relation tothe respective aorta with intact endothelium (Table1). Moreover, the removal of the endothelium eliminated the aortichyper-reactivity to noradrenaline observed in stress and stress/ethanol groups (Figure 2A). None of the protocols altered thereactivity to noradrenaline in denuded aortas (Figures2B, 2C and 2D),nor did they affect the reactivity to phenylephrine (Figures 3A and 3B) in intact or denudedaortas. Similar phenylephrine EC50 were also observed among the groups (Table 2).

Bottom Line: EC50 and maximum response (n=8-12) were compared using two-way ANOVA/Bonferroni method.Meanwhile, ethanol consumption did not alter the reactivity to noradrenaline.This effect is dependent upon the vascular endothelium and involves the release of vasoconstrictor prostanoids via stimulation of endothelial alpha-2 adrenoceptors.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, São Paulo, SP, Brasil.

ABSTRACT

Background: Stress and ethanol are both, independently, important cardiovascular risk factors.

Objective: To evaluate the cardiovascular risk of ethanol consumption and stress exposure, isolated and in association, in male adult rats.

Methods: Rats were separated into 4 groups: Control, ethanol (20% in drinking water for 6 weeks), stress (immobilization 1h day/5 days a week for 6 weeks) and stress/ethanol. Concentration-responses curves to noradrenaline - in the absence and presence of yohimbine, L-NAME or indomethacin - or to phenylephrine were determined in thoracic aortas with and without endothelium. EC50 and maximum response (n=8-12) were compared using two-way ANOVA/Bonferroni method.

Results: Either stress or stress in association with ethanol consumption increased the noradrenaline maximum responses in intact aortas. This hyper-reactivity was eliminated by endothelium removal or by the presence of either indomethacin or yohimbine, but was not altered by the presence of L-NAME. Meanwhile, ethanol consumption did not alter the reactivity to noradrenaline. The phenylephrine responses in aortas both with and without endothelium also remained unaffected regardless of protocol.

Conclusion: Chronic stress increased rat aortic responses to noradrenaline. This effect is dependent upon the vascular endothelium and involves the release of vasoconstrictor prostanoids via stimulation of endothelial alpha-2 adrenoceptors. Moreover, chronic ethanol consumption appeared to neither influence noradrenaline responses in rat thoracic aorta, nor did it modify the increase of such responses observed as a consequence of stress exposure.

Show MeSH
Related in: MedlinePlus