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Mechanism of vasorelaxation induced by Tridax procumbens extract in rat thoracic aorta.

Salahdeen HM, Idowu GO, Salami SA, Murtala BA, Alada AA - J Intercult Ethnopharmacol (2016)

Bottom Line: The results showed that the TPE (0.5-9.0 mg/ml) significantly (P < 0.05) reduced the contraction induced by PE in a concentration-dependent manner.These results suggest that TPE causes vasodilatory effects in a concentration-dependent manner in the isolated rat aortic artery.The mechanism of action of TPE is complex.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, College of Medicine, Lagos State University, Ikeja, Lagos, Nigeria.

ABSTRACT

Background/aim: Tridax procumbens (Linn) (Asteraceae) is one of the herbs widely distributed in many parts of the world. Its leaves have long been used for the treatment of hypertension in Nigeria. Previous studies have shown that aqueous leaves of T. procumbens extract (TPE) lowers blood pressure through endothelium-dependent and -independent mechanism in the aortic rings isolated from normotensive rats. The aim of the present study was to further investigate mechanisms of TPE-induced relaxation in the aortic artery by assessing its mechanistic interactions with nitric oxide (NO) synthase, cyclic guanosine monophosphate (cGMP), and cyclic adenosine monophosphate (cAMP).

Materials and methods: The aortic artery isolated from healthy, young adult normotensive Wistar albino rats (250-300 g) were pre-contracted with phenylephrine (PE) (10-7 M) and KCl (60 mM) and were treated with various concentrations of aqueous extract of TPE (0.5-9.0 mg/ml). The changes in arterial tension were recorded using Ugo Basile model 7004 coupled to data capsule acquisition system model 17400. The interaction between TPE with cAMP and cGMP inhibitors was also evaluated.

Results: The results showed that the TPE (0.5-9.0 mg/ml) significantly (P < 0.05) reduced the contraction induced by PE in a concentration-dependent manner. The vasorelaxant effect caused by the TPE was significantly (P < 0.05) attenuated with pre-incubation of cGMP (Rp-8Br PET cGMPS) and cAMP (Rp-AMP) inhibitor, respectively.

Conclusion: These results suggest that TPE causes vasodilatory effects in a concentration-dependent manner in the isolated rat aortic artery. The mechanism of action of TPE is complex. A part of its relaxing effect is mediated directly by blocking or modulating cGMP and cAMP.

No MeSH data available.


Related in: MedlinePlus

Typical tracing showing the vasorelaxant effects of graded concentration of TPE a (a) Phenylephrine (10–7 M) (PE)-induced and (b) (60 mM) KCl-induced contraction in the endothelium-intact aortic ring isolated from normotensive rat. Arrows 1-6 represent cumulatively administered TPE (0.3, 0.6, 0.9, 1.2, 1.5, and 1.8 mg/ml, respectively) administration of drup upward-arrow (P) and washed out at (W) downward-arrow
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Figure 1: Typical tracing showing the vasorelaxant effects of graded concentration of TPE a (a) Phenylephrine (10–7 M) (PE)-induced and (b) (60 mM) KCl-induced contraction in the endothelium-intact aortic ring isolated from normotensive rat. Arrows 1-6 represent cumulatively administered TPE (0.3, 0.6, 0.9, 1.2, 1.5, and 1.8 mg/ml, respectively) administration of drup upward-arrow (P) and washed out at (W) downward-arrow

Mentions: Figure 1 shows the typical tracing of relaxation responses to TPE (0.3-1.8 mg/ml) recorded in aortic ring pre-contracted by PE [Figure 1a] or by KCl [Figure 1b]. The tension developed was significantly reduced by cumulative application of TPE.


Mechanism of vasorelaxation induced by Tridax procumbens extract in rat thoracic aorta.

Salahdeen HM, Idowu GO, Salami SA, Murtala BA, Alada AA - J Intercult Ethnopharmacol (2016)

Typical tracing showing the vasorelaxant effects of graded concentration of TPE a (a) Phenylephrine (10–7 M) (PE)-induced and (b) (60 mM) KCl-induced contraction in the endothelium-intact aortic ring isolated from normotensive rat. Arrows 1-6 represent cumulatively administered TPE (0.3, 0.6, 0.9, 1.2, 1.5, and 1.8 mg/ml, respectively) administration of drup upward-arrow (P) and washed out at (W) downward-arrow
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835993&req=5

Figure 1: Typical tracing showing the vasorelaxant effects of graded concentration of TPE a (a) Phenylephrine (10–7 M) (PE)-induced and (b) (60 mM) KCl-induced contraction in the endothelium-intact aortic ring isolated from normotensive rat. Arrows 1-6 represent cumulatively administered TPE (0.3, 0.6, 0.9, 1.2, 1.5, and 1.8 mg/ml, respectively) administration of drup upward-arrow (P) and washed out at (W) downward-arrow
Mentions: Figure 1 shows the typical tracing of relaxation responses to TPE (0.3-1.8 mg/ml) recorded in aortic ring pre-contracted by PE [Figure 1a] or by KCl [Figure 1b]. The tension developed was significantly reduced by cumulative application of TPE.

Bottom Line: The results showed that the TPE (0.5-9.0 mg/ml) significantly (P < 0.05) reduced the contraction induced by PE in a concentration-dependent manner.These results suggest that TPE causes vasodilatory effects in a concentration-dependent manner in the isolated rat aortic artery.The mechanism of action of TPE is complex.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, College of Medicine, Lagos State University, Ikeja, Lagos, Nigeria.

ABSTRACT

Background/aim: Tridax procumbens (Linn) (Asteraceae) is one of the herbs widely distributed in many parts of the world. Its leaves have long been used for the treatment of hypertension in Nigeria. Previous studies have shown that aqueous leaves of T. procumbens extract (TPE) lowers blood pressure through endothelium-dependent and -independent mechanism in the aortic rings isolated from normotensive rats. The aim of the present study was to further investigate mechanisms of TPE-induced relaxation in the aortic artery by assessing its mechanistic interactions with nitric oxide (NO) synthase, cyclic guanosine monophosphate (cGMP), and cyclic adenosine monophosphate (cAMP).

Materials and methods: The aortic artery isolated from healthy, young adult normotensive Wistar albino rats (250-300 g) were pre-contracted with phenylephrine (PE) (10-7 M) and KCl (60 mM) and were treated with various concentrations of aqueous extract of TPE (0.5-9.0 mg/ml). The changes in arterial tension were recorded using Ugo Basile model 7004 coupled to data capsule acquisition system model 17400. The interaction between TPE with cAMP and cGMP inhibitors was also evaluated.

Results: The results showed that the TPE (0.5-9.0 mg/ml) significantly (P < 0.05) reduced the contraction induced by PE in a concentration-dependent manner. The vasorelaxant effect caused by the TPE was significantly (P < 0.05) attenuated with pre-incubation of cGMP (Rp-8Br PET cGMPS) and cAMP (Rp-AMP) inhibitor, respectively.

Conclusion: These results suggest that TPE causes vasodilatory effects in a concentration-dependent manner in the isolated rat aortic artery. The mechanism of action of TPE is complex. A part of its relaxing effect is mediated directly by blocking or modulating cGMP and cAMP.

No MeSH data available.


Related in: MedlinePlus