Blackwood W D, Bolinger R A, Lifson N
J Clin Invest. 1973 Jan;52(1):143-52. doi: 10.1172/JCI107158.
It has been confirmed that the rabbit vermiform appendix secretes spontaneously at a relatively rapid rate (1-12 ml.h(-1); 1.4+/-0.24 mul.min(-1).cm(-2)). The electrolyte composition is similar to that of ileal fluids and independent of the secretory rate. The transmural potential difference is about 12 mV, mucosa negative. Of the major electrolytes, only HCO(3) (-) is secreted grossly against its electrochemical potential difference. This finding plus the low hydraulic (or osmotic) permeability (L(p)) and high secretory pressures of the organ strongly suggest that the secretion is an active one. The passive permeability to Na(+) and Cl(-) appears to be, at most, somewhat less than for small bowel. Permeability to mannitol was estimated at 2.5 x 10(-7) cm.s(-1). On the basis of reasonable assumptions and results with luminal test solutions of differing osmolarities, it was concluded that (a) the L(p) of the appendiceal epithelium is in the lower range of values reported for small bowel and colon; (b) the L(p) is higher for osmotic absorption than for osmotic secretion; and (c) the rate of spontaneous secretion is insensitive to luminal anisotonicity over a wide range of values. But sufficiently hypotonic solutions can reverse net secretion to net absorption, more by inhibiting spontaneous secretion than increasing osmotic absorption. The rabbit vermiform appendix appears to be a useful model for the elucidation of intestinal secretory processes.
已证实兔阑尾能以相对较快的速率自发分泌（1 - 12 ml·h⁻¹；1.4 ± 0.24 μl·min⁻¹·cm⁻²）。其电解质组成与回肠液相似，且与分泌速率无关。跨壁电位差约为12 mV，黏膜呈负电位。在主要电解质中，只有HCO₃⁻明显逆其电化学势差分泌。这一发现加上该器官较低的水力（或渗透）通透性（L(p)）和较高的分泌压力，强烈表明这种分泌是主动分泌。对Na⁺和Cl⁻的被动通透性似乎至多比小肠略低。对甘露醇的通透性估计为2.5×10⁻⁷ cm·s⁻¹。基于合理假设和不同渗透压腔内测试溶液的结果，得出以下结论：(a)阑尾上皮的L(p)处于小肠和结肠报道值的较低范围；(b)渗透吸收的L(p)高于渗透分泌的L(p)；(c)在很宽的值范围内，自发分泌速率对腔内非等渗状态不敏感。但足够低渗的溶液可使净分泌逆转至净吸收，更多是通过抑制自发分泌而非增加渗透吸收实现。兔阑尾似乎是阐明肠道分泌过程的有用模型。
