Efeito vasodilatador do extrato metanólico de Erythroxylum caatingae Plowman sobre anéis mesentéricos de ratos espontaneamente hipertensos (SHR)
Authors: Reis Milena Ramos , Albuquerque Jamile M. de , Tavares Josean F. , Silva Darizy F. 
Published: May 2018

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</style> <![endif]--> <p class="MsoNormal" style="margin: 0cm 22.7pt 0.0001pt; text-align: justify;"><strong><span style="font-size: 8pt; color: black;">Introdução: </span></strong><em><span style="font-size: 8pt;">Erythroxylum caatingae</span></em><span style="font-size: 8pt;"> Plowman (ETC) tem revelado a presença de diversos alcalóides com atividade biológica. <strong>Objetivo:</strong> Avaliar a potencial ação anti-hipertensiva do extrato metanólico da espécie <span style="color: black;">ETC sobre anéis de artéria mesentérica superior isolada de ratos espontaneamente hipertensos (SHR). </span><strong>Metodologia:</strong> Para isto, foram realizados ensaios farmacológicos <em>in vitro,</em> e o efeito vasodilatador de ETC (0,01-300 µg/mL) foi observado. <strong>Resultados:</strong> Em anéis mesentéricos isolados, com endotélio funcional intacto e pré-contraídos com fenilefrina (FEN) (1 µM), ETC induziu relaxamento (CE</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">50</span><span style="font-size: 8pt;"><span> </span>= 14.49 (20.5 – 29.2) µg/mL; E</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">máx</span><span style="font-size: 8pt;"><span> </span>= 110,11 ± 2.4 %; n = 7), de maneira dependente da concentração do extrato e este efeito não foi atenuado após remoção do endotélio vascular (CE</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">50</span><span style="font-size: 8pt;"><span> </span>= 27.41 (21.1 – 35.6) µg/mL; E</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">máx</span><span style="font-size: 8pt;"><span> </span>= 116.7 ± 8.0 %; n = 7; p < 0.05). Estes resultados sugerem que a resposta vasodilatadora induzida por ETC independe dos fatores vasoativos liberados pelo endotélio. Por isso, os experimentos subsequentes foram realizados com preparações na ausência da camada endotelial. Em anéis pré-contraídos com serotonina, ETC apresentou aumento na potência farmacológica, quando comparado aos anéis pré-contraídos com a FEN (CE</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">50</span><span style="font-size: 8pt;"><span> </span>= 9.22 (5.8 – 14.6) µg/mL; n = 11; p < 0.001), entretanto, não houve diferença significante em relação ao seu efeito máximo (E</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">máx</span><span style="font-size: 8pt;"><span> </span>= 112.97 ± 3.5 %; n = 11; p < 0.05). Enquanto que, em anéis pré-contraídos com solução despolarizante de KCl (60 mM), a curva concentração-resposta para ETC não foi significativamente diferente à obtida em anéis pré-contraídos com FEN (CE</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">50</span><span style="font-size: 8pt;"><span> </span>= 20.76 (16.2 – 26.6) µg/mL; E</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;">máx</span><span style="font-size: 8pt;"><span> </span>= 106.94 ± 3.6 %, n = 8; p < 0.05). <strong>Conclusão:</strong> Tomados juntos, estes dados sugerem que ETC promove vasodilatação em anéis mesentéricos de animal SHR, independente da presença do endotélio vascular, e estes efeitos são mais potentes em tônus contraído por ativação de receptores serotoninérgicos, quando comparados a outros vasocontracturantes.</span></p><p class="MsoNormal" style="margin: 0cm 22.7pt 0.0001pt; text-align: justify;"> </p><p class="MsoNormal" style="margin: 0cm 22.7pt 0.0001pt; text-align: justify;"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:HyphenationZone>21</w:HyphenationZone> <w:PunctuationKerning /> <w:ValidateAgainstSchemas /> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables /> <w:SnapToGridInCell /> <w:WrapTextWithPunct /> <w:UseAsianBreakRules /> <w:DontGrowAutofit /> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style>

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</style> <![endif]--></p><p class="MsoNormal" style="margin: 0cm 22.7pt 0.0001pt; text-align: justify;"><strong><span style="font-size: 8pt; color: black;" lang="EN-US">Introduction: </span></strong><em><span style="font-size: 8pt;" lang="EN-US">Erythroxylum caatingae</span></em><span style="font-size: 8pt;" lang="EN-US"> Plowman (ETC) has revealed the presence of several alkaloids with biological activity. <strong>Objective:</strong> Evaluate the potential antihypertensive action of methanol extract from ETC species in superior mesenteric artery rings isolated from spontaneously hypertensive rats (SHR). <strong>Methods:</strong> Pharmacological tests were performed <em>in vitro</em> and the vasorelaxant effect of ETC (0.01-300 µg/mL) was observed. <strong>Results:</strong> In isolated mesenteric rings with a functional and intact endothelium, pre-contracted with phenylephrine (PHE) (1 µM), ETC induced relaxation [EC</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;" lang="EN-US">50</span><span style="font-size: 8pt;" lang="EN-US"><span> </span>= 14.49 (20.5 - 29.2) µg/mL; MR = 110.11 ± 2.4%, n = 7] in a concentration dependent manner. This effect was not attenuated after removal of the vascular endothelium [EC</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;" lang="EN-US">50</span><span style="font-size: 8pt;" lang="EN-US"><span> </span>= 27.41 (21.1 - 35.6) µg/mL; MR = 116.7 ± 8.0%, n = 7, p<0.05]. These results suggest that the vasodilator response induced by ETC is independent of endothelium derived vasoactive factors. Therefore, subsequent experiments were performed in endothelium removed mesenteric rings. In rings pre-contracted with serotonin, ETC had an increased pharmacological potency when compared to rings pre-contracted with PHE [EC</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;" lang="EN-US">50</span><span style="font-size: 8pt;" lang="EN-US"><span> </span>= 9.22 (5.8 - 14.6) µg/mL, n = 11, p<0.001], but not significant difference with respect to its maximum effect (MR = 112.97 ± 3.5%, n = 11, p<0.05). In rings pre-contracted with a depolarizing solution of KCl (60 mM), the concentration-response curve for ETC was not significantly different to that obtained in rings pre-contracted with PHE [EC</span><span style="font-size: 4.5pt; position: relative; top: 2.5pt;" lang="EN-US">50</span><span style="font-size: 8pt;" lang="EN-US"><span> </span>= 20.76 (16.2 - 26.6) µg/mL, MR = 106.94 ± 3.6%, n = 8, p<0.05]. <strong>Conclusion:</strong> Taken together, these findings suggest that ETC promotes vasodilation in mesenteric rings from SHR animals, independent of the presence of the vascular endothelium, and these effects have a more potent impact on vascular tone of upon activation serotonin receptors, when compared to other vasoconstricting agents.</span></p>