Jahr J, Ekelund U, Grände P O
Department of Physiology and Biophysics, University of Lund, Sweden.
Crit Care Med. 1995 Mar;23(3):523-31. doi: 10.1097/00003246-199503000-00018.
To analyze the local circulatory effects of prostacyclin in skeletal muscle.
A prospective experimental study.
A university laboratory.
Twelve adult cats.
The study was performed on autoperfused, sympathectomized gastrocnemius muscle.
Arterial blood flow, total and segmental vascular resistances (arterial vessels of > 25 microns, arterioles of < 25 microns, and veins), hydrostatic capillary pressure, tissue volume, myogenic reactivity, and the capillary filtration coefficient were followed. The capillary filtration coefficient reflects the functional capillary fluid exchange area. Myogenic reactivity was evaluated as the arteriolar resistance increase after a standardized decrease in extravascular pressure. Arterial infusion of prostacyclin decreased vascular resistance by approximately 50% at the highest dose given (500 ng/kg/min). This effect was more pronounced on the arterial side, especially in arterial vessels of > 25 microns. Hydrostatic capillary pressure increased by 1.9 +/- 0.3 mm Hg, causing fluid filtration. The relative fluid filtration was less than that value shown for some other vasodilator drugs (isoprenaline, calcium-channel blockers, thiopental) in this muscle preparation. Capillary filtration coefficient decreased by 25%. Myogenic reactivity was depressed but to a lesser extent than previously observed for other vasodilator mechanisms (muscle exercise, beta-adrenergic receptor stimulation, thiopental infusion, nifedipine infusion).
Prostacyclin is a vasodilator, both on the arterial and venous side, that restricts the increase in hydrostatic capillary pressure. The decrease in capillary filtration coefficient most likely reflects a decrease in capillary permeability, explaining the smaller relative filtration rate. The relatively well-preserved myogenic reactivity may imply a better preserved microvascular flow distribution and peripheral oxygen uptake.
分析前列环素对骨骼肌局部循环的影响。
前瞻性实验研究。
大学实验室。
12只成年猫。
在自体灌注、去交感神经的腓肠肌上进行研究。
记录动脉血流量、总血管阻力及各节段血管阻力（直径>25微米的动脉血管、直径<25微米的小动脉及静脉）、毛细血管静水压、组织体积、肌源性反应性以及毛细血管滤过系数。毛细血管滤过系数反映功能性毛细血管液体交换面积。肌源性反应性通过血管外压力标准化降低后小动脉阻力的增加来评估。动脉内输注前列环素，在给予的最高剂量（500纳克/千克/分钟）时，血管阻力降低约50%。这种作用在动脉侧更为明显，尤其是在直径>25微米的动脉血管中。毛细血管静水压升高1.9±0.3毫米汞柱，导致液体滤过。相对液体滤过低于该肌肉制剂中其他一些血管扩张剂（异丙肾上腺素、钙通道阻滞剂、硫喷妥钠）所显示的值。毛细血管滤过系数降低25%。肌源性反应性受到抑制，但程度低于先前观察到的其他血管扩张机制（肌肉运动、β-肾上腺素能受体刺激、硫喷妥钠输注、硝苯地平输注）。
前列环素在动脉和静脉侧均为血管扩张剂，可限制毛细血管静水压的升高。毛细血管滤过系数的降低很可能反映了毛细血管通透性的降低，这解释了相对滤过率较小的原因。相对较好保留的肌源性反应性可能意味着微血管血流分布和外周氧摄取得到较好保留。
