Sjövall H, Redfors S, Biber B, Jodal M, Lundgren O
Scand J Gastroenterol. 1984 May;19(3):411-6.
The aim of the study was to investigate the effects of dopamine on the intestinal mucosal blood flow and transport function. Dopamine was infused intravenously at 20 micrograms X kg-1 X min-1 in anesthetized cats. Total and intramural blood flow in an isolated jejunal segment was measured by a combined drop-flow and 85Kr clearance technique. Net fluid transport was recorded by two independent perfusion methods. Unidirectional sodium transport was estimated from luminal 22Na disappearance. Dopamine induced a pronounced mucosal vasodilatation up to 400% of control values. Concomitantly, net fluid and sodium absorption increased by 50%. The effect on sodium transport was due to a pronounced decrease in tissue-to-lumen sodium flux, a pattern similar to the one seen on alpha-adrenergic stimulation. The effect of dopamine on blood flow was unaffected by phentolamine, 1 mg X kg-1, whereas the absorptive response was abolished. The findings indicate that dopamine induces a mucosal vasodilation via one mechanism (possibly dopaminergic) and enhances fluid transport via another mechanism, probably alpha-adrenergic.
本研究的目的是探讨多巴胺对肠黏膜血流和转运功能的影响。在麻醉猫中，以20微克/千克/分钟的速度静脉输注多巴胺。采用滴流和85氪清除技术联合测量离体空肠段的总血流量和壁内血流量。通过两种独立的灌注方法记录净液体转运。根据管腔内22钠的消失情况估算单向钠转运。多巴胺可使黏膜血管显著扩张，达到对照值的400%。与此同时，净液体和钠的吸收增加了50%。对钠转运的影响是由于组织到管腔的钠通量显著降低，这一模式与α-肾上腺素能刺激时所见相似。多巴胺对血流的影响不受1毫克/千克酚妥拉明的影响，而吸收反应则被消除。这些发现表明，多巴胺通过一种机制（可能是多巴胺能机制）诱导黏膜血管舒张，并通过另一种机制（可能是α-肾上腺素能机制）增强液体转运。
