SEGMENTAL HETEROGENEITY OF EPITHELIAL TRANSPORT IN RAT LARGE-INTESTINE
SEGMENTAL HETEROGENEITY OF EPITHELIAL TRANSPORT IN RAT LARGE-INTESTINE
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DOI：
10.1007/bf00581960
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发表时间：
1978-01-01
影响因子：
4.5
通讯作者：
HEGEL, U
中科院分区：
文献类型：
--
作者：
FROMM, M;HEGEL, U
功能分离的大鼠结肠和直肠段在闭环系统中原位灌注。直肠定义为大肠长度的下25-35%（盲肠除外）。优化灌注条件为0.5 ml/min， 3 cm H2O管压。0.2 ~ 2ml /min灌注率变化对净体积输送无影响。**GRAPHIC**。静水压力升高至18 cm H2O后管腔扩张可逆增加。**图**。在控制条件下。**图形**。和Na+传输速率。**图形**。结肠的发生率是直肠的2 ~ 3倍。在结肠中，经上皮电位差（.psi.ms）是时间依赖性的- 12mV（管腔阴性），而直肠中。从-6mV开始，ms随时间的增加而增加，在6 h内达到-67mV的平稳值。女士,* *图形* *。和* *图形* *。但能轻微降低结肠降液中K+的分泌。在10-4 mol/l时，直肠内ms呈剂量依赖性降低，可逆转至+7mV。和* *图形* *。减少了一半。乙酰唑胺和阿米洛利一起降低阿米洛利后直肠阳性。一半的女士。肾上腺切除术对结肠psi无影响。Ms，但废除了。psi。直肠的Ms。单次剂量40亩。G /kg醛固酮可恢复直肠正常血压的正常时间。Ms，但不影响。psi。冒号女士。醛固酮仅在直肠诱导了对氨溴胺敏感的Na+通路，而在结肠中没有，结肠和直肠的运输性质在数量和质量上基本不同，肾远端弯曲小管和皮质集管也是如此。
Functionally isolated segments of rat colon and rectum were perfused in situ in a closed loop system. Rectum was defined as the lower 25-35% of the length of large intesinte (cecum excluded). Perfusion conditions were optimized at 0.5 ml/min and 3 cm H2O luminal pressure. Variation of perfusion rate between 0.2 and 2 ml/min did not influence net volume transport .**GRAPHIC**. Luminal distension following elevation of hydrostatic pressure to 18 cm H2O reversibly increased .**GRAPHIC**. Under control conditions .**GRAPHIC**. and Na+-transport rates .**GRAPHIC**. of colon were 2-3 times higher than those of rectum. In colon transepithelial electrical potential difference (.psi.ms) was time-dependent - 12mV (lumen negative), whereas rectal .psi.ms increased with time from -6mV, reaching a plateau of -67mV within 6 h. Amiloride 10-4 mol/l had no effect on .psi.ms, .**GRAPHIC**. and .**GRAPHIC**. in colon but did slightly depress K+-secretion in colon descendens. .psi.ms in rectum was dose-dependently depressed, being reversed to +7mV at 10-4 mol/l. .**GRAPHIC**. and .**GRAPHIC**. were decreased by half. Acetazolamide in addition to amiloride lowered the positive post-amiloride rectal .psi.ms by half. Adrenalectomy had no effect on colonic .psi.ms, but abolished .psi.ms of the rectum. A single dose of 40 .mu.g/kg aldosterone during the experiment restored the typical time course of rectal .psi.ms, but did not affect .psi.ms in colon. Aldosterone induces an amiloride-sensitive Na+-pathway only in rectum, but not in colon, and that colon and rectum differ basically in their transport properties, quantitatively as well as qualitatively, as do the kidney distal convoluted tubule and the cortical collecting duct.