Merker M P, Gillis C N
Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut 06510.
J Appl Physiol (1985). 1988 Dec;65(6):2579-84. doi: 10.1152/jappl.1988.65.6.2579.
Indicator dilution technique was used to study effects of reduced vascular volume or acute injury on removal of low doses of [3H]propranolol and [14C]serotonin (5-hydroxytryptamine, 5-HT) by perfused rabbit lung. Glass-bead (500 micron) embolization doubled pulmonary arterial pressure (Ppa) at flow rates of 20, 50, and 100 ml/min, decreased volume of distribution by approximately 50%, and increased pulmonary vascular resistance by at least 60%. Before embolization, (flow rate 20 ml/min) removal of [3H]propranolol and [14C] 5-HT was 89 +/- 2 and 75 +/- 5%, respectively, and was unaltered by changes in flow rate. However, after embolization, [3H]propranolol and [14C]5-HT removal decreased in a flow-dependent manner, reaching 28 +/- 4 and 1 +/- 3% (P less than 0.05), respectively, at a flow rate of 100 ml/min. When phorbol myristate acetate (PMA, 200 nM) was perfused (50 ml/min) through the lungs for 15 min, Ppa increased from 13 +/- 1 to 25 +/- 2 cmH2O (P less than 0.05), whereas [3H]propranolol removal decreased from 92 +/- 1 to 75 +/- 5% (P less than 0.05) and [14C]5-HT removal decreased from 73 +/- 3 to 46 +/- 8% (P less than 0.05). The PMA also caused vasoconstriction, which could be partially blocked by adding papaverine (500 microM) to the perfusion medium. Under the latter conditions, Ppa increased to 19 +/- 1 cmH2O and [3H]propranolol removal was unaffected. However, the combination of PMA and papaverine reduced [14C]5-HT removal from 64 +/- 4 to 19 +/- 3%.(ABSTRACT TRUNCATED AT 250 WORDS)
采用指示剂稀释技术研究血管容积减少或急性损伤对灌注兔肺清除低剂量[3H]普萘洛尔和[14C]5-羟色胺（5-HT）的影响。玻璃珠（500微米）栓塞在流速为20、50和100毫升/分钟时使肺动脉压（Ppa）加倍，分布容积减少约50%，肺血管阻力增加至少60%。栓塞前（流速20毫升/分钟），[3H]普萘洛尔和[14C]5-HT的清除率分别为89±2%和75±5%，且不受流速变化影响。然而，栓塞后，[3H]普萘洛尔和[14C]5-HT的清除率呈流量依赖性降低，在流速为100毫升/分钟时分别降至28±4%和1±3%（P<0.05）。当佛波酯肉豆蔻酸酯（PMA，200纳摩尔）以50毫升/分钟的流速灌注肺15分钟时，Ppa从13±1厘米水柱增加至25±2厘米水柱（P<0.05），而[3H]普萘洛尔的清除率从92±1%降至75±5%（P<0.05），[14C]5-HT的清除率从73±3%降至46±8%（P<0.05）。PMA还引起血管收缩，可通过向灌注液中添加罂粟碱（500微摩尔）部分阻断。在后者条件下，Ppa增加至19±1厘米水柱，[3H]普萘洛尔的清除率未受影响。然而，PMA与罂粟碱联合使用使[14C]5-HT的清除率从64±4%降至19±3%。（摘要截断于250字）
