Pentoxifylline relaxes isolated pulmonary arteries after preconstriction with norepinephrine.
Pentoxifylline relaxes isolated pulmonary arteries after preconstriction with norepinephrine.
复制标题
去甲肾上腺素预收缩后，己酮可可碱可松弛孤立的肺动脉。
DOI：
10.1159/000195818
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Reed,WP
中科院分区：
文献类型：
--
作者：
Crowell,RE;Chick,TW;Reed,WP
戊乙茶碱（PTX）是一种甲基黄嘌呤衍生物，其可能通过对血小板聚集和红细胞变形性的作用来改善全身微血管流动和组织氧递送。尽管PTX也能改善肺血管血流，但最近的证据表明，这种改善的部分原因可能是肺血管舒张。为了评价这些作用，我们研究了离体兔叶肺动脉（PA）环段，以确定PTX是否对PA组织有直接作用，以及这些作用是否可以通过血管或内皮破坏来调节。在静息张力下，PTX对PA无影响。然而，如果PA张力被去甲肾上腺素（5 μM）主动增加，随后的PTX应用引起浓度依赖性PA舒张。松弛迅速发生，并在45-60秒内达到最大。松弛所需的阈值PTX浓度为1 μM。PTX诱导的舒张不受环氧合酶抑制剂吲哚美辛（1 μM）预处理的影响。轻轻摩擦内膜PA表面的内皮破坏废除了由乙酰胆碱预收缩PA的松弛，但对PTX的松弛没有影响。尽管在静息张力下PA对PTX无反应，但在PTX浓度> 10 μ M时，去甲肾上腺素引起的PA收缩显著减少。这些数据表明PTX对分离的兔PA具有直接作用，其不被吲哚美辛阻断，也不需要完整内皮的存在。PTX能抑制去甲肾上腺素引起的PA收缩
Pentoxifylline (PTX) is a methylxanthine derivative which improves systemic microvascular flow and tissue oxygen delivery, presumably through actions on platelet aggregation and erythrocyte deformability. Although PTX also improves pulmonary vascular flow, recent evidence suggests that part of this improvement may be due to pulmonary vasodilation. To evaluate these effects we studied isolated rabbit lobar pulmonary artery (PA) ring segments to determine if PTX had direct effects on PA tissues and whether these effects could be modulated pharmacologically or by endothelial disruption. PTX had no effect on PA at resting tension. However, if the PA tension was actively increased by norepinephrine (5 μM), subsequent PTX application caused concentration-dependent PA relaxation. Relaxation occurred promptly and was maximal within 45–60 s. The threshold PTX concentration necessary for relaxation was 1 μM. PTX-induced relaxation was not affected by pretreatment with the cyclo-oxygenase inhibitor indomethacin (1 μM). Endothelial disruption by gentle rubbing of the intimal PA surface abolished relaxation of preconstricted PA by acetylcholine, but had no effect on relaxation by PTX. Although PA at resting tension displayed no response to PTX, PA constriction by norepinephrine in the presence of PTX concentrations > 10 μMwas significantly decreased. These data indicate that PTX has direct actions on isolated rabbit PA which are not blocked by indomethacin nor require the presence of intact endothelium. Furthermore, PTX can suppress norepinephrine-induced constriction of isolated PA