Vascular Pharmacology of Mokuboito (Mu-Fang-Yi-Tang) and Its Constituents on the Smooth Muscle and the Endothelium in Rat Aorta

Pharmacological actions of Mokuboito and its constituents (Sinomenium acutum and sinomenine) on rat aorta were examined. Mokuboito and S. acutum at lower concentrations (0.03–1 mg ml−1) contracted the non-loaded aorta, but at higher concentrations (1–3 mg ml−1), reversed to dilate it. The vasoconstriction was blocked by phentolamine (10 μM). Sinomenine failed to exhibit the vasoconstriction. On the other hand, Mokuboito and S. acutum dilated the NE (5 μM)-induced vasoconstriction: at 3 mg ml−1, by 98.9 ± 2.5% (n = 6, P < 0.01) and 97.0 ± 4.8% (n = 6, P < 0.01). Vasorelaxation induced by Mokuboito and S. acutum was attenuated by indomethacin, L-NMMA and nicardipine. Propranolol decreased the vasorelaxation induced by Mokuboito, but not by S. acutum. Sinomenine also relaxed the constriction and at 100 μM, by 68.8 ± 5.1% (n = 7, P < 0.01). This vasorelaxation was attenuated by indomethacin, L-NMMA and nicardipine, and also by propranolol. Therefore, these results indicate that Mokuboito and its constituents exert both vasodilating actions mediated by endothelium-dependent mechanisms (PGI2 and NO from endothelium) and by endothelium-independent mechanisms (Ca2+ influx control on smooth muscle cells). Simultaneously, Mokuboito and S. acutum cause the vasoconstrictions mediated through α-adrenoceptor stimulation, but not sinomenine. Also, Mokuboito and sinomenine possess β-adrenoreceptor stimulating action, but not S. acutum

The Role of Apelin on the Alleviative Effect of Angiotensin Receptor Blocker in Unilateral Ureteral Obstruction-Induced Renal Fibrosis

Background: Apelin is a selective endogenous ligand of the APJ receptor, which genetically has closest identity to the angiotensin II type 1 receptor (AT-1). The effects of the apelin/APJ system on renal fibrosis still remain unclear. Methods: We examined the effects of the apelin/APJ system on renal fibrosis during AT-1 blockade in a mouse unilateral ureteral obstruction (UUO) model. Results: We obtained the following results: (1) At UUO day 7, mRNA expressions of apelin/APJ and phosphorylations of Akt/endothelial nitric oxide synthase (eNOS) in the UUO kidney were increased compared to those in the nonobstructed kidney. (2) AT-1 blockade by the treatment with losartan resulted in a further increase of apelin mRNA as well as phosphorylations of Akt/eNOS proteins, and this was accompanied by alleviated renal interstitial fibrosis, decreased myofibroblast accumulation, and a decreased number of interstitial macrophages. (3) Blockade of the APJ receptor by the treatment with F13A during losartan administration completely abrogated the effects of losartan in the activation of the Akt/eNOS pathway and the amelioration of renal fibrosis. (4) Inhibition of NOS by the treatment with L-NAME also resulted in a further increase in renal fibrosis compared to the control group. Conclusion: These results suggest that increased nitric oxide production through the apelin/APJ/Akt/eNOS pathway may, at least in part, contribute to the alleviative effect of losartan in UUO-induced renal fibrosis

Cardiovascular Pharmacology of Sinomenine: The Mechanical and Electropharmacological Actions

Sinomenine is one of the alkaloids extracted from Chinese medical plant, Sinomenium acutum Rehder et Wilson. Sinomenine has been used for Rheumatoid arthritis as an anti-inflammatory and immunomodulative drugs. We have so far been investigated the cardiovascular pharmacological actions of sinomenine. Sinomenine dilated NE (5 μM)-, KCl (60 mM)- and PDB (300 nM)-induced vasoconstrictions. The pretreatment with nicardipine (0.1 μM), staurosporine (30 nM), L-NMMA (100 μM), indomethacin (10 μM) or propranolol significantly attenuated the sinomenine-induced vasorelaxation. Therefore, these results indicate that sinomenine causes the vasorelaxation by the involvement with the inhibitions of Ca 2+ current (I Ca ) and PK-C, β-adrenoceptor stimulation, and the activation of NO and PGI 2 syntheses in endothelium. On the other hand, in the ventricular cardiomyocytes of guinea pig, sinomenine inhibits I Ca and simultaneously decreases the delayed rectifier K + current (I K ), resulting in the prolongation of action potential duration. Sinomenine also suppresses the dysrhysmias induced by triggered activities under the Ca 2+ overload condition. Therefore, sinomenine may be expected as one of effective therapeutic drugs for heart failure and dysrhythmias, and may maintain the cardiovascular functions due to modulation of cardiac ionic channels and blood vessels