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Objective To investigate the vasodilating effects of protocatechuic aldehyde (PCA ) on rat superior mesenteric arterial rings as well as its mechanism .Methods The tension of rat superior mesenteric arterial rings was recorded by a sensitive myograph system in vitro . We measured isometric tension changes in preconstricted rat superior mesenteric artery rings induced by potassium chloride (KCl ,60 mmol/L) ,serotomin (5-HT ,10-5 mol/L ) , and phenylephrine (PE , 10-5 mol/L ) after PCA treatment at different concentrations , respectively .We also observed vasodilating effects of PCA on KCl (60 mmol/L ) preconstricted rat superior mesenteric arterial rings after incubation with different inhibitors ,i .e .,L-NAME ,Indo ,ODQ ,4-AP (KV channel blocker) ,TEA (KCa channel blocker) ,BaCl2 (Kir channel blocker) ,and Glib (KATP channel blocker) ,respectively . Results PCA (10-6 -10-3 mol/L ) could relax KCl (60 mmol/L ) and 5-HT (10-5 mol/L ) preconstricted rat superior mesenteric arterial rings in a concentration-dependent manner . Indo of endothelial mechanism inhibitor blocked the vasodilating effect of PCA . 4-AP and BaCl2 of potassium ion channel inhibitors affected the vasodilatation induced by PCA in KCl (60 mmol/L)-preconstricted rat mesenteric artery .Conclusion PCA can relax KCl (60 mmol/L) ,or 5-HT preconstricted rat superior mesenteric arterial rings .This effect is associated with the inhibition of potassium channels and endothelial mechanism .
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Aim To investigate the effect of 15-ketoeicosatetraenoic acid(15-KETE)and its mechanism through ion channels on rat isolated pulmonary arterial rings by using organ bath technique.Methods Sixteen healthy Wistar rats weighing 220?20 g were divided into two groups(n=8): normoxia group breathing fresh air(FiO_2=21%) and hypoxia group breathing hypoxic air(FiO_2=10%) in a hypoxic box.Pulmonary arteries(PA)were extracted after 9 d and cut into rings(0.5~1.0 mm in diameter and 3 mm in length) for organ bath experiments.Results(1) With increasing concentration from 0 to10~(-6) mol?L~(-1),15-KETE increased PA rings tension gradually in a dosedependent fashion;(2) 4-aminopyridine(2 mmol?L~(-1)),a Kv channel blocker significantly decreased constriction of rat isolated PA rings induced by 15-KETE,and results were similar in two groups;(3) The K_(ATP) channel blocker glyburide(10~(-6)6 mol?L~(-1)) and the BK_(Ca) channel blocker tetraethylammonium(10 mmol?L~(-1)) did not affect constriction of rat isolated PA rings induced by 15-KETE;(4) The BKCa channel blocker nifedipine(10~(-6) mol?L~(-1)) and Ca~(2+)-free Krebs solution significantly decreased constriction of rat isolated PA rings induced by 15-KETE.Conclusion Kv channels play a role in constriction of PA induced by 15-KETE;L-type Ca~(2+) channel blocker and extracellular calcium ion also influence constriction of isolated PA rings induced by 15-KETE.
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Aim The purpose of this study was to compare the effect of AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE on hypoxic and normoxic rabbit pulmonary arterial rings and to discuss their roles in the formation of PA hypertension.Methods Twelve neonatal rabbits were randomly divided into two groups(n=6):the normoxic group breathing fresh gas(FiO_2 =21%) and the hypoxic group breathing hypoxic gas(FiO_2=10%).After 9 days,they were anesthetized with pentobarbital sodium,and the chest was opened for removal of the heart and lungs en bloc,then PA rings(0.5~1.5 mm in diameter and 3 mm length) were prepared.We used tension studies of PA rings to observe the effect of AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE on hypoxic and normoxic rabbit pulmonary arterial rings.Results ① AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE constricted normoxic rabbit PA rings in a dose-dependent manner,respectively.Constriction of normoxic rabbit PA rings induced by 15-KETE、8(S),15(S)-DiHETE was significant,but that of AA、15-HETE wasn′t significant.② AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE increased hypoxic rabbit PA rings' tension.Constriction of AA、15-HETE on rabbit PA rings in hypoxic group was significantly greater than that of normoxic group(P0.05).③ Constriction of 15-KETE on rabbit PA rings in normoxic group was significantly greater than that of hypoxia group(P
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Objective To investigate the effect of Prunellu vulgaris L.extracts on isolated rabbit artery. Methods The effect of Prunellu vulgaris L.extracts on the contraction curve caused by norepinephrine (NE) was recorded on isolated rabbit artery. Results The contraction curve moved to the right and the maximum contraction range was decreased by chloroform extract, butanol extract and ethyl acetate extract; the contraction curve had no move by aquatic extract. Conclusion Prunellu vulgaris L. has the effect of dilating artery and reducing blood pressure.