Discovery of novel 2-benzylisoquinolin-1(2H)-ones as potent vasodilative agents.

2-Benzylisoquinolin-1(2H)-ones has been proposed as vasodilative agents on the basis of scaffold hopping. In the present study, a series of 2-benzylisoquinolin-1(2H)-ones were synthesized. Their vasodilative effects were evaluated by wire myograph on isolated rat mesenteric arterial ring induced contraction with 60mM KCl. The structure-activity relationships of target compounds were discussed. Among these compounds, C7 and C8 displayed potent vasodilative effects and significantly inhibited the contraction of rat mesenteric arterial rings induced by phenylephrine. The antihypertensive effects of compounds C7 and C8 on SHR were further evaluated. The results indicated that oral administrational C7 and C8 can significantly reduce both diastolic and systolic blood pressure in a dose-dependent manner. Moreover, C7 maintained the effects for 4h at a dosage of 4.0mg/kg. These findings suggest that the title compounds can serve as novel vasodilative agents and promising antihypertensive agents.

Discovery of novel 3-benzylquinazolin-4(3H)-ones as potent vasodilative agents.

In the present study, a series of 3-benzylquinazolin-4(3H)-ones were synthesized and characterized. Their vasodilative effects were evaluated by wire myograph on isolated rat mesenteric arterial ring induced contraction with 60mM KCl. The SAR of target compounds was discussed preliminarily. Among these compounds, 2a and 2c displayed potent vasodilatation action and could compete significantly the rat mesenteric arterial rings induced contraction with phenylephrine. Compounds 2a and 2c were further tested for their antihypertensive effects in SHR by oral administration. The results indicated that 2a and 2c could reduce significantly both diastolic and systolic blood pressure. Moreover, 2c displayed antihypertensive effect in a dose dependent manner, and could maintain the effects for 6h at a dosage of 4.0mg/kg. These findings suggest that the title compounds are novel vasodilative agents, representing a novel series of promising antihypertensive agents.

Paeonol induces vasodilatation in rat mesenteric artery via inhibiting extracellular Ca²âº influx and intracellular Ca²âº release.

OBJECTIVE: To investigate the vasodilative effect of paeonol in rat mesenteric artery and the mechanisms responsible for it. METHODS: Rats were anaesthetized and sacrificed. The superior mesenteric artery was removed, dissected free of adherent tissue and cut into 2.0 mm long cylindrical segments. Isometric tension of artery rings was recorded by a myograph system in vitro. Concentration-relaxation curves of paeonol (17.8 µ mol/L to 3.16 mmol/L) were recorded on artery rings precontracted by potassium chloride (KCl) and concentration-contraction curves of KCl, 5-hydroxytryptamine (5-HT), noradrenaline (NA) or calcium chloride (CaCl2) were recorded in the presence of paeonol (10(-4.5), 10(-3.8), 10(-3.5) mol/L) respectively. And also, concentration-relaxation curves of paeonol were recorded in the presence of different potassium channel inhibitors and propranolol on rings precontracted with KCl respectively. To investigate the role of intracellular Ca(2+) release from Ca(2+) store, the contraction induced by NA (100 µ mol/L) and CaCl2 (2 mmol/L) in Ca(2+) free medium was observed in the presence of paeonol respectively. RESULTS: Paeonol relaxed artery rings precontracted by KCl in a concentration-dependent manner and the vasodilatation effect was not affected by endothelium denudation. Paeonol significant decreased the maximum contractions (Emax) induced by KCl, CaCl2, NA and 5-HT, as well as Emax induced by NA and CaCl2 in Ca(2+) -free medium, suggesting that paeonol dilated the artery via inhibiting the extracellular Ca(2+) influx mediated by voltage-dependent calcium channel, and receptor-mediated Ca(2+)-influx and release. Moreover, none of glibenclamide, tetraethylammonium, barium chlorded and propranolol affected the paeonol-induced vasodilatation, indicating that the vasodilatation was not contributed to ATP sensitive potassium channel, calcium-activated potassium channel, inwardly rectifying potassium channel, and ß-adrenoceptor. CONCLUSION: Paeonol induces non-endothelium dependent-vasodilatation in rat mesenteric artery via inhibiting voltage-dependent calcium channel-mediated extracellular Ca(2+) influx and receptor-mediated Ca(2+) influx and release.

[The pharmacological mechanism of gastrodin on calcitonin gene-related peptide of cultured rat trigeminal ganglion].

The Chinese herbal medicine Tianma (Gastrodia elata) has been used for treating and preventing primary headache over thousands of years, but the exact pharmacological mechanism of the main bioactive ingredient gastrodin remains unclear. In present study, the effects of gastrodin on calcitonin gene-related peptide (CGRP) and phosphorylated extracellular signal-regulated kinase1/2 (pERK1/2) expression were observed in rat trigeminal ganglion (TG) after in vitro organ culture to explore the underlying intracellular mechanism of gastrodin on primary vascular-associated headache. CGRP-immunoreactivity (CGRP-ir) positive neurons count, positive area, mean optical density and integrated optical density by means of immunohistochemistry stain were compared at different concentrations of gastrodin, which was separately co-incubated with DMEM in SD rat TG for 24 hours. Only at 5 or 10 mmol L(-1) concentration, gastrodin demonstrated significantly concentration-dependent reduction of CGRP-ir (+) expression and its action closed to 1.2 mmol L(-1) sumatriptan succinate. While at 2.5, 20, and 40 mmol L(-1) concentration, gastrodin did not show remarkable effects on CGRP-ir (+) expression. The optimal concentration of gastrodin (5 and 10 mmol L(-1)) similarly inhibited CGRP-mRNA expression level separately compared with 1.2 mmol L(-1) sumatriptan succinate and 10 micromol L(-1) flunarizine hydrochloride, which was quantitatively analyzed by real-time PCR (RT-PCR). pERK1/2 level was examined by Western blotting after co-cultured with optimal concentration of gastrodin and effective specific ERK1/2 pathway inhibitors PD98059, U0126. The result indicated that gastrodin significantly reduced pERK1/2 protein actions similarly to ERK1/2 pathway specific blockade. It suggests ERK1/2 signaling transduction pathway may be involved in gastrodin intracellular mechanism. This study indicates gastrodin (5 and 10 mmol L(-1)) can remarkably reduce CGRP-ir (+) neuron, CGRP-mRNA and pERK1/2 expression level in cultured rat TG, with its actions similar to the effective concentration of sumatriptan succinate, flunarizine hydrochloride and specific ERK1/2 pathway blocker. The intracellular signaling transduction ERK1/2 pathway may be involved in the gastrodin reducing CGRP up-regulation in rat TG after organ culture.

Effects of daidzein sulfates on blood pressure and artery of rats.

The aim of this study is to investigate the hypotensive and vasodilator effects of daidzein sulfates, a water-solubility derivative of daidzein. Tail cuff blood pressure of spontaneously hypertensive rat (SHR) was measured with non-invasive Electro-Sphygmomanometer. An isometric tension of rat mesenteric artery ring segments was recoded in vitro on a myograph. The results showed that daidzein sulfates (20 and 40 mg/kg) could decrease blood pressure of SHR in single dose and multi-doses. Daidzein sulfates (1-100 microM) inhibited the contraction of rat mesenteric arterial ring segments induced by norepinephrine (NA) and 5-hydroxytryptamine (5-HT). Daidzein sulfates (100-1000 microM) inhibited arterial segment's contraction induced by KCl and CaCl(2). The concentration- contractive curves were shifted toward right in a non-parallel manner with decreased E(max.) Daidzein sulfaltes inhibited the extracellular Ca(2+)-dependent contraction. Daidzein sulfates of 100 and 300 microM significantly inhibited the contraction induced by CaCl(2) in Ca(2+)-free solution, which is an extracellular Ca(2+)-dependent contraction; but daidzein sulfates did not inhibit the intracellular Ca(2+)-dependent NA-induced contraction, in Ca(2+)-free solution. The results suggest that daidzein sulfates possess significant hypotensive and vasodilator effects which mainly derive from artery smooth muscle cells by inhibiting the receptor-mediated Ca(2+)-influx.