Ozono K, Bosnjak Z J, Kampine J P
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee.
Am J Physiol. 1989 Apr;256(4 Pt 2):H1066-72. doi: 10.1152/ajpheart.1989.256.4.H1066.
We have directly demonstrated that the mesenteric veins actively constrict and dilate in response to reflex stimuli in the in situ preparation. A segment of small intestine of 23 chloralose-anesthetized rabbits was exposed in a specially designed bath. Small vein diameter and intravenous pressure (575-1,375 microns and 6.2-11.4 mmHg at rest, respectively) of the mesentery were measured continuously at the same site with the use of videomicrometer and micropressure systems during celiac ganglion stimulation (CGS), bilateral carotid occlusion (BCO), and aortic nerve stimulation (ANS). Innervation to the mesenteric vein was evident by a frequency-dependent venoconstriction in response to CGS, which was completely abolished by local application of tetrodotoxin. Vein diameter and intravenous pressure changed from an average of 1,042 +/- 32 to 1,003 +/- 32 microns (-3.8 +/- 0.3%, P less than 0.01) and from 8.1 +/- 0.3 to 9.0 +/- 0.3 mmHg (10.6 +/- 0.8%, P less than 0.01), respectively, during BCO. During ANS, vein diameter increased from 990 +/- 32 to 1,012 +/- 31 microns (2.4 +/- 0.2%, P less than 0.01), and intravenous pressure decreased from 8.5 +/- 0.3 to 7.9 +/- 0.2 mmHg (-6.1 +/- 0.6%, P less than 0.01), respectively. Vein diameter changes of -3.8 and 2.4% corresponded to volume changes of -7.6 and 4.9%, respectively. During BCO, vein diameter decreased while intravenous pressure increased, whereas during ANS vein diameter increased while intravenous pressure decreased. These results indicate that the reflex change in vein diameter is due to an active response.
我们已经直接证明，在原位制备中，肠系膜静脉会对反射刺激做出主动收缩和舒张反应。将23只氯醛糖麻醉的兔子的一段小肠暴露在一个特别设计的浴槽中。在刺激腹腔神经节（CGS）、双侧颈动脉闭塞（BCO）和刺激主动脉神经（ANS）期间，使用视频显微镜和微压力系统在同一部位连续测量肠系膜小静脉直径和静脉压力（静息时分别为575 - 1375微米和6.2 - 11.4毫米汞柱）。对CGS的频率依赖性静脉收缩表明存在对肠系膜静脉的神经支配，局部应用河豚毒素可完全消除这种收缩。在BCO期间，静脉直径从平均1042±32微米变为1003±32微米（-3.8±0.3%，P<0.01），静脉压力从8.1±0.3毫米汞柱变为9.0±0.3毫米汞柱（10.6±0.8%，P<0.01）。在ANS期间，静脉直径从990±32微米增加到1012±31微米（2.4±0.2%，P<0.01），静脉压力从8.5±0.3毫米汞柱降至7.9±0.2毫米汞柱（-6.1±0.6%，P<0.01）。静脉直径-3.8%和2.4%的变化分别对应于-7.6%和4.9%的容积变化。在BCO期间，静脉直径减小而静脉压力升高，而在ANS期间静脉直径增加而静脉压力降低。这些结果表明静脉直径的反射性变化是由于主动反应所致。
