Korean J Physiol Pharmacol.  2016 Jan;20(1):69-74. 10.4196/kjpp.2016.20.1.69.

Cardamonin inhibits agonist-induced vascular contractility via Rho-kinase and MEK inhibition

• Je HD
• Jeong JH

• KMID: 2150475
• DOI: http://doi.org/10.4196/kjpp.2016.20.1.69

Abstract

The present study was undertaken to investigate the influence of cardamonin on vascular smooth muscle contractility and to determine the mechanism(s) involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Cardamonin significantly relaxed fluoride-, phenylephrine-, and phorbol ester-induced vascular contractions, suggesting that it has an anti-hypertensive effect on agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, cardamonin significantly inhibited the fluoride-induced increase in pMYPT1 level and phenylephrine-induced increase in pERK1/2 level, suggesting inhibition of Rho-kinase and MEK activity and subsequent phosphorylation of MYPT1 and ERK1/2. This study provides evidence that the relaxing effect of cardamonin on agonist-induced vascular contraction regardless of endothelial function involves inhibition of Rho-kinase and MEK activity.

Keyword

Cardamonin; ERK1/2; Fluoride; MYPT1; Rho-kinase

MeSH Terms

Animals
Fluorides
Humans
Isometric Contraction
Male
Muscle, Smooth, Vascular
Nitric Oxide
Phosphorylation
Rats
rho-Associated Kinases*
Fluorides
Nitric Oxide
rho-Associated Kinases

Figure

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  Fig. 1 The chemical structure of cardamonin ((E)-1-(2,4-dihydroxy-6-methoxyphenyl)-3-phenylprop-2-en-1-one).

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  Fig. 2 Effect of cardamonin on fluoride-induced vascular contraction in denuded (A) or intact (B) muscles.Each ring was equilibrated in organ bath solution for 30~60 min before relaxation responses to cardamonin were measured. Data are expressed as the means of 3~5 experiments with vertical lines representing SEMs. *p<0.05, **p<0.01, presence versus absence of cardamonin.

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  Fig. 3 Effect of cardamonin on phenylephrine-induced vascular contraction.Each ring was equilibrated in organ bath solution for 30~60 min before relaxation responses to cardamonin were measured. Data are expressed as the means of 3~5 experiments with vertical lines representing SEMs. *p<0.05, **p<0.01, presence versus absence of cardamonin.

• 

  Fig. 4 Effect of cardamonin on phorbol ester-induced vascular contraction.Each ring was equilibrated in organ bath solution for 30~60 min before relaxation responses to cardamonin were measured. Data are expressed as the means of 3~5 experiments with vertical lines representing SEMs. *p<0.05, **p<0.01, presence versus absence of cardamonin.

• 

  Fig. 5 Effect of cardamonin on fluoride-induced increases in phospho-MYP T1 levels.Phospho-MYPT1 protein levels were significantly decreased in rapidly-frozen cardamonin-treated rat aorta in the absence of endothelium compared to vehicle-treated rat aorta precontracted with fluoride. The upper panel shows a typical blot and the lower panel shows average densitometry results for relative levels of phospho-MYPT1. Data are expressed as the means of 3~5 experiments with vertical lines representing SEMs. *p<0.05, ##p<0.01, versus control or normal group respectively. Carda: 0.1 mM cardamonin; Fluoride: 6 mM sodium fluoride.

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  Fig. 6 Effect of cardamonin on the phenylephrine-induced increase in phospho-ERK1/2 level.Phospho-ERK1/2 protein level was decreased in rapidly-frozen cardamonin-treated rat aortas in the absence of endothelium than vehicle-treated rat aortas precontracted with a phorbol ester. The upper panel shows a typical blot and the lower panel shows average densitometry results for relative levels of phospho-ERK1/2. Data are expressed as the means of 3-5 experiments with vertical lines representing SEMs. ##p<0.01, versus normal group respectively. Cardamonin: 0.1 mM cardamonin; Phenylephrine: 1 µM phenylephrine.

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  Fig. 7 Effect of cardamonin on the fluoride-induced increase in phospho-MLC20 level.Phospho-MLC20 levels expressed as a percentage of total MLC20 were significantly lower in rapidly-frozen cardamonin-treated rat aorta in the absence of endothelium than vehicle-treated rat aorta precontracted with fluoride (6 mM). Data are expressed as the means of 3~5 experiments with vertical lines representing SEMs. *p<0.05, ##p<0.01, versus control or normal group respectively. Cardamonin: 0.1 mM cardamonin; Fluoride: 6 mM sodium fluoride.

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