[Vasorelaxational effects of total alkali Sophora alopecuroids on rabbit aorta in vitro].

OBJECTIVE: To study the vasodilation effects of the Total alkali Sophora alopecuroids L (TASa) on rabbit thoracic aortic rings in vitro and the possible mechanisms. METHOD: Rabbit aortic rings were isolated and precontracted with noradrenaline (NA) and then were divided into six groups including control group, TASa group, TASa + 1 x 10(-5) mol x L(-1) indomethacin (Indo), TASa + 1 x 10(-5) mol x L(-1) propranolol (Prop), TASa + 1 x 10(-10 mol x L(-1) N(omega)-nitro-L-arginine (L-NNA), TASa + removal of endothelium. The vasodilation effects of TASa were investigated. In addition, the thoracic aortic rings were pre-treated with TASa (40 mg x L(-1)) and then the thoracic aortic rings were treated with cumulative NA (110(-8)-110(-5) mol x L(-1)), KCl (6.3-100 mmol x L(-1)) or CaCl2 (110(-5)-110(-2) mol x L(-1)). The dose response curves of aortic rings were recorded. RESULT: TASa can relax isolated rabbit aorta and has an obvious concentration-dependent relaxation (r = 0.94, P < 0.01). The relaxant effect of TASa was no significant reducing by removal of endothelium and by treatment with L-NNA, Indo or Prop. In addition, TASa can decrease the dose response curves of aortic rings to NA, KCl or CaCl2. CONCLUSION: The vasodilation effects of TASa are related to not only inhibition of intracellular calcium release, but also reduction to calcium flow to the interior of the cell with blockage of calcium channels.

[Vasorelaxant effects of procyanidins on rabbit pulmonic ring in vitro].

OBJECTIVE: To study the vasorelaxant effect of procyanidin (PC) extracted from grape seeds on rabbit thoracic pulmonic rings in vitro. METHOD: Rabbits thoracic pulmonic rings were isolated, pre-contracted with noradrenalin (NA) and their responses to different concentrations of PC were investigated. The effects of endothelium and different signaling pathway inhibitors on PC-induced relaxation, including nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (L-NNA), methylene blue (MB), prostaglandin synthase inhibitor indomethacin (Indo) and blockage of the adrenergic beta-receptor propranolol (Prop), were also assessed. RESULT: PC change the resting tension of rabbit's pulmonic rings but caused an obvious dose-dependent relaxation in 1 x 10(-6) mol x L(-) NA precontracted pulmonic rings (r = 0.69, P < 0.01). The relaxant effect of PC was significantly reduced by removal of endothelium or by treatment with either 1 x 10(-4) mol x L(-1) L-NNA or 1 x 10(-5) mol L(-1) MB, but not by treatment with prostaglandin synthase inhibitor or blockage of the adrenergic beta-receptor. In addition, PC (20 mg x L(-1)) dropped the dose-effect curves of NA, KCl and respectively on pulmonic rings denuded endothelium. PC can also inhibit the vasoconstriction caused by NA in the first phase, but has no impact on the constriction induced by CaCl2 in the second phase. CONCLUSION: PC has an endothelium-dependent vasorelaxation on isolated rabbit's pulmonic rings, which is possibly mediated by nitric oxide (NO) pathways and blockage of receptor operated and voltage dependent calcium channels.

[Vasorelaxational effects of procyanidins on rabbit aorta in vitro and decreasing arterial blood pressure in vivo].

OBJECTIVE: To study the vasodilation effect of the procyanidin (PC) extracted from grape seeds on rabbit thoracic aortic rings in vitro, decreasing blood pressure in vivo and the possible mechanism. METHOD: Rabbits aortic rings were isolated and were divided into six groups including removal of endothelium, integrity of endothelium, 1 x 10(-5) mol X L(-1) indomethacin (Indo), 1 x 10(-5) mol x L(-1) propranolol (Prop), 1 x 10(-4) mol x L(-1) N(omega)-nitro-L-arginine (L-NNA) and 1 x 10(-5) mol x L(-1) methylene blue (MB). Then the thoracic aortic rings were treated with PC with cumulative concentrations of 1.25, 2.5, 5.0 mg x L(-1) respectively and the changes of tension were recorded, and investigate the effect of 40 mg x L(-1) PC on the contraction of aortic smooth muscles, thoracic aortic rings were pre-treated with NA (1 x 10(-8) to approximately 1 x 10(-5) mol x L(-1)), KCl (6.3 to approximately 100 mmol x L(-1)) and CaCl2 (1 x 10(-5) to approximately 1 x 10(-5) mol x L(-1)) followed by treatment with PC. Then, rabbits common carotid artery was intubated and arterial blood pressure in vivo was recorded. PC with cumulative concentrations of 4.0, 8.0, 16, 32, 64, 84 mg x kg(-1) was injected into vein and the changes of arterial blood pressure were observed. RESULT: PC could relax isolated rabbit aorta and showedan obvious concentration-dependent relaxation (r = 0. 63, P < 0.001). The relaxant effect of PC was significantly reduced by removal of endothelium and by treatment with nitric oxide synthase inhibitor L-NNA, or guanylyl cyclase inhibitor MB. In addition PC could decrease the dose response curves of aortic rings to NA, KCl and CaCl2. PC has a significant concentration-dependent negative effect on arterial blood pressure in vivo (r = 0.92, P < 0.001). CONCLUSION: PC has a vasodilation effect not only in an endothelium-dependent, nitric oxide involved manner, but in inhibition of calcium release and blockage of potential-dependent calcium channels. PC could decrease the rabbit's arterial blood pressure significantly in vivo.