Rutlen D L, Helgesen K G, Christensen G, Vengen O A, Ilebekk A
Cardiology Section, Yale University School of Medicine, New Haven, Connecticut 06510.
Acta Physiol Scand. 1990 Aug;139(4):569-73. doi: 10.1111/j.1748-1716.1990.tb08960.x.
The present study examined the influence of angiotensin on total intravascular capacity. In eight anaesthetized pigs, splenectomy, carotid sinus denervation and cervical vagotomy were performed. Blood was drained from the venae cavae to an extracorporeal reservoir and returned to the right atrium at a constant rate so that changes in total intravascular volume could be recorded as the inverse of changes in reservoir volume. Angiotensin administration at 0.2 microgram kg-1 min-1 i.v. for 5 min was associated with a decrease in total intravascular volume of 57 +/- 6 ml (P less than 0.05) and an increase in aortic pressure from 96 +/- 5 to 119 +/- 6 mmHg (P less than 0.05). With subsequent angiotensin administration in five of the animals, the responses were not attenuated. In five of the animals, angiotensin was associated with a decrease in intravascular volume of 72 +/- 8 ml (P less than 0.05) before abdominal evisceration and 33 +/- 13 ml (P less than 0.05) after evisceration. These responses were significantly different from each other. In four of these eviscerated animals, angiotensin was associated with a decrease in intravascular volume of 35 +/- 17 ml (P less than 0.05) before ligation of all four limbs and a decrease of 36 +/- 4 ml (P less than 0.05) after limb ligation. Thus, angiotensin acts directly to decrease total intravascular volume. The decrease is due to decreases in both splanchnic and extrasplanchnic volume. The extrasplanchnic volume decrement is not due to decreases in skeletal muscle or cutaneous tissue intravascular capacity in the limbs.
本研究考察了血管紧张素对血管总容量的影响。对8只麻醉猪进行了脾切除术、颈动脉窦去神经支配术和颈迷走神经切断术。将腔静脉血液引流至体外储液器，并以恒定速率回输至右心房，以便将血管总容量的变化记录为储液器容量变化的倒数。以0.2微克/千克体重/分钟的速率静脉注射血管紧张素5分钟，血管总容量减少57±6毫升（P<0.05），主动脉压从96±5毫米汞柱升高至119±6毫米汞柱（P<0.05）。随后对其中5只动物再次注射血管紧张素，反应未减弱。在其中5只动物中，血管紧张素在开腹前使血管内容量减少72±8毫升（P<0.05），开腹后减少33±13毫升（P<0.05）。这些反应彼此有显著差异。在其中4只开腹动物中，血管紧张素在结扎四肢前使血管内容量减少35±17毫升（P<0.05），结扎四肢后减少36±4毫升（P<0.05）。因此，血管紧张素直接作用于减少血管总容量。这种减少是由于内脏和内脏外容量均减少所致。内脏外容量的减少并非由于四肢骨骼肌或皮肤组织血管容量的减少。
