Regulation of capillary exchange capacity in postnatal swine intestine.
Regulation of capillary exchange capacity in postnatal swine intestine.
复制标题
产后猪肠道毛细血管交换能力的调节。
DOI：
10.1152/ajpgi.1993.265.6.g1090
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Miller,CE
中科院分区：
文献类型：
--
作者：
Nowicki,PT;Miller,CE
为了确定是否内在调节毛细血管交换能力是年龄依赖性在出生后的早期生活，我们测量了毛细血管过滤系数（Kf，c），毛细血管交换能力的指数，在离体灌注肠从3日龄和35日龄的猪在不同的动脉压。Kf，c通过重量分析法测定，通过流动平衡技术。在与年龄相适应的压力下进行基线灌注期间，35日龄与3日龄肠的Kf，c平均值分别为0.203 +/-0.020与0.361 +/-0.040 ml. min-1 x mmHg-1 x 100 g。在老年动物中，随着动脉压降低，观察到Kf，c逐渐升高：当压力降低至基线以下20%、40%和60%时，Kf，c分别升高至基线以上14%、35%和98%。Kf、c与血流量呈负相关。在进行性低血压期间，3日龄小肠的Kf，c也增加，但这些变化的幅度较小：当压力降低至基线以下20%、40%和60%时，Kf，c平均分别高于基线19%、17%和23%。与老年动物的情况相反，Kf，c和血流量之间的关系在3日龄肠内不显着。以1 μ g/min的速度动脉内灌注异丙肾上腺素（一种已知可增加毛细血管交换能力的药物），可使3日龄肠组的Kf，c增加80%。我们的结论是，Kf，c增加到更大程度上在35日龄比3日龄的猪肠道动脉压降低。然而，年轻动物的肠道能够增加毛细血管交换能力，以响应动脉低血压以外的刺激，如其对异丙肾上腺素的反应所证明的。
To determine whether intrinsic regulation of capillary exchange capacity is age-dependent during early postnatal life, we measured the capillary filtration coefficient (Kf,c), an index of capillary exchange capacity, within isolated perfused intestine from 3- and 35-day-old swine at different arterial pressures. Kf,c was determined gravimetrically, by means of the flow-equilibration technique. During baseline perfusion at age-appropriate pressures, Kf,c averaged 0.203 +/- 0.020 vs. 0.361 +/- 0.040 ml.min-1 x mmHg-1 x 100 g in 35- vs. 3-day-old intestine. In older animals, a progressive rise in Kf,c was noted as arterial pressure was lowered: Kf,c increased 14, 35, and 98% above baseline when pressure was reduced 20, 40, and 60% below baseline, respectively. An inverse linear correlation between Kf,c and blood flow was demonstrated in this group. Kf,c also increased in 3-day-old intestine during progressive hypotension, but these changes were of less magnitude: Kf,c averaged 19, 17, and 23% above baseline when pressure was reduced 20, 40, and 60% below baseline, respectively. In contrast to the circumstance noted in older animals, the relationship between Kf,c and blood flow was not significant within 3-day-old intestine. Intraarterial infusion of 1 microgram/min of isoproterenol, an agent known to increase capillary exchange capacity, caused Kf,c to increase 80% within 3-day-old intestine group. We conclude that Kf,c increases to a greater extent in 35- than 3-day-old swine intestine in response to arterial pressure reduction. However, intestine from younger animals is capable of increasing capillary exchange capacity in response to stimuli other than arterial hypotension, as evidenced by its response to isoproterenol.