Perry M A, Granger D N
Am J Physiol. 1981 Jul;241(1):G24-30. doi: 10.1152/ajpgi.1981.241.1.G24.
The permeability of capillaries in the isolated, vascularly perfused cat ileum was studied with the double-indicator diffusion technique. The molecules studied were raffinose, inulin, and beta-lactoglobulin A. Plasma flow through the tissue was increased by local intra-arterial infusions of isoproterenol (a selective mucosal vasodilator) or adenosine (a dilator of the muscularis vasculature). The permeability-surface area product (PS) for all solutes increased with increasing plasma flow. At the highest plasma flow acquired with isoproterenol, PS values for raffinose, inulin, and beta-lactoglobulin A were approximately 40, 20, and 4 ml.min-1.100 g-1, respectively. These data suggest that capillaries in the mucosa-submucosa of the ileum are at least five to seven times more permeable to raffinose and inulin than has been reported for skeletal muscle capillaries. Selective vasodilation of the muscularis region with adenosine reduced PS values for raffinose and inulin at each flow rate studied. The data are consistent with equivalent pore radii of approximately 60 A for capillaries in the mucosa-submucosa and 40 A in the muscularis of the small intestine.
采用双指示剂扩散技术，对离体、血管灌注的猫回肠毛细血管的通透性进行了研究。所研究的分子为棉子糖、菊粉和β-乳球蛋白A。通过局部动脉内输注异丙肾上腺素（一种选择性黏膜血管舒张剂）或腺苷（一种肌层血管舒张剂）来增加流经组织的血浆流量。所有溶质的通透表面积乘积（PS）随血浆流量增加而升高。在用异丙肾上腺素获得的最高血浆流量下，棉子糖、菊粉和β-乳球蛋白A的PS值分别约为40、20和4 ml·min⁻¹·100 g⁻¹。这些数据表明，回肠黏膜-黏膜下层的毛细血管对棉子糖和菊粉的通透性至少比骨骼肌毛细血管所报道的高五到七倍。用腺苷对肌层区域进行选择性血管舒张，在每个研究的流量下，棉子糖和菊粉的PS值均降低。数据表明，小肠黏膜-黏膜下层毛细血管的等效孔径约为60 Å，肌层为40 Å。
