ABSTRACT
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.
ABSTRACT
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