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首页> 外文期刊>Life sciences >Vasomotion in rat mesentery during hemorrhagic hypotension.
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Vasomotion in rat mesentery during hemorrhagic hypotension.

机译：失血性低血压期间大鼠肠系膜的血管运动。

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Although vasomotion has been considered a feature of the microvascular bed under physiological conditions, it has also been observed following hypotension in several tissues. In this work, 158 mesenteric microvessels of 36 rats were investigated quantitatively in normovolemic and hemorrhaged animals, focussing on diameter changes, particularly vasomotion incidence and characteristics. The femoral arteries of Wistar rats (body weight BW = 188 +/- 23 g, mean +/- SD) anesthetized with pentobarbital were cannulated for arterial pressure (AP) monitoring and blood withdrawal. The protocol consisted of 15 min control and 30 min of hemorrhagic hypotension (AP = 52 +/- 5 mmHg, hemorrhaged vol. = 17 +/- 4 ml/kg BW). During control normovolemic conditions, analysis of mesenteric microcirculation using intravital videomicroscopy revealed neither arteriolar nor venular vasomotion. During hemorrhagic hypotension (HH) microvascular blood flow reduced to 25% of control. While venules did not show diameter changes during HH, arterioles contracted to 85 +/- 20% of control and arteriolar vasomotion appeared in 42% of the animals and 27% of the arterioles. The amplitude of arteriolar diameter change during HH relative to mean diameter and to control diameter averaged 65 +/- 24% (range: 32-129%) and 41 +/- 10% (range: 25-62%), respectively. Vasomotion analysis showed two major frequency components: 1.7 +/- 0.8 and 7.0 +/- 5.2 cycles/min. Arterioles showing vasomotion had a mean control diameter larger than the remaining arterioles and showed the largest constriction during HH. We conclude that hemorrhagic hypotension does not change venular diameter but induces arteriolar constriction and vasomotion in rat mesentery. This activity is expressed as slow waves with high amplitude and fast waves with low amplitude, and is dependent on vessel size.
机译：尽管血管舒张被认为是生理条件下微血管床的特征，但在几种组织中发生低血压后也已观察到血管舒张。在这项工作中，对正输血和出血动物中36只大鼠的158条肠系膜微血管进行了定量研究，重点是直径变化，尤其是血管运动发生率和特征。将戊巴比妥麻醉的Wistar大鼠（体重BW = 188 +/- 23 g，平均+/- SD）的股动脉插管以监测动脉压（AP）和抽血。该方案包括15分钟的对照和30分钟的出血性低血压（AP = 52 +/- 5 mmHg，出血量= 17 +/- 4 ml / kg BW）。在正常血容量正常情况下，使用活体视频显微镜对肠系膜微循环进行分析后，未发现小动脉或小静脉的血管运动。在出血性低血压（HH）期间，微血管血流量减少至对照的25％。尽管在HH期间小静脉未显示直径变化，但小动脉收缩至对照的85 +/- 20％，小动脉血管运动出现在42％的动物和27％的小动脉中。 HH期间相对于平均直径和对照直径的小动脉直径变化幅度分别平均为65 +/- 24％（范围：32-129％）和41 +/- 10％（范围：25-62％）。 Vasomotion分析显示两个主要频率分量：1.7 +/- 0.8和7.0 +/- 5.2个循环/分钟。显示血管运动的小动脉的平均控制直径大于其余小动脉，并且在HH期间显示最大的收缩。我们得出的结论是，出血性低血压不会改变静脉直径，但会引起大鼠肠系膜的小动脉收缩和血管运动。此活动表示为高振幅的慢波和低振幅的快波，并取决于血管的大小。

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