Jacobson E D, Gallavan R H, Fondacaro J D
Am J Physiol. 1982 Jun;242(6):G541-6. doi: 10.1152/ajpgi.1982.242.6.G541.
A model of the mesenteric microcirculation is proposed that explains three observed variations in the hyperemic response of the small intestine to different dilator stimuli. The model assumes a two-component circulation in which one component delivers more than enough blood flow and oxygen to meet the metabolic demands of the resting tissue served by this "flow-independent component." The second portion, known as the "flow-limited component" delivers an insufficient blood supply for tissue needs and, therefore, restricts the metabolism of the parenchyma it serves. The three types of reported hyperemic responses are a) hyperemia induced by certain drugs, such as nifedipine and acetylcholine, in which case only the flow-limited component is dilated and one observes an increase in blood flow to the gut without any increase in intestinal oxygen consumption; b) hyperemia induced by stimulating active cotransport of nutrients from the intestinal lumen, in which case the tissue served by the flow-independent component increases its metabolism and oxygen demand, resulting in an increase in oxygen consumption that exceeds proportionately the increase in blood flow; and c) hyperemia induced by other vasodilator drugs, such as adenosine, in which case both vascular components are dilated and both blood flow and oxygen uptake are increased, but the increase in blood flow is proportionately greater than the increase in oxygen consumption.
提出了一种肠系膜微循环模型，该模型解释了小肠对不同扩张刺激的充血反应中观察到的三种变化。该模型假定存在双组分循环，其中一个组分输送的血流量和氧气量超过满足由该“非血流依赖组分”供应的静息组织代谢需求所需的量。第二部分，即“血流限制组分”，输送的血液供应不足以满足组织需求，因此限制了其所供应实质组织的代谢。所报道的三种充血反应类型为：a）由某些药物（如硝苯地平和乙酰胆碱）诱导的充血，在这种情况下，仅血流限制组分扩张，观察到肠道血流量增加而肠道耗氧量无任何增加；b）通过刺激营养物质从肠腔的主动协同转运诱导的充血，在这种情况下，非血流依赖组分供应的组织增加其代谢和氧气需求，导致耗氧量增加，其增加幅度超过血流量增加的比例；c）由其他血管扩张药物（如腺苷）诱导的充血，在这种情况下，两个血管组分均扩张，血流量和氧气摄取均增加，但血流量增加的比例大于耗氧量增加的比例。
