Paracellular absorption: a bat breaks the mammal paradigm.
Paracellular absorption: a bat breaks the mammal paradigm.
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DOI：
10.1371/journal.pone.0001425
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发表时间：
2008-01-09
期刊：
影响因子：
3.7
通讯作者：
Otani L
中科院分区：
文献类型：
--
作者：
Caviedes-Vidal E;Karasov WH;Chediack JG;Fasulo V;Cruz-Neto AP;Otani L
蝙蝠的肠道组织往往比体型庞大的非飞行哺乳动物要少。肠道体积的相应减少以及所携带的体重的相应减少是有利的，因为飞行成本随着携带的重量而增加，并且因为起飞和机动性在更重的重量下降低。水溶性化合物，如葡萄糖和氨基酸，在小肠中主要通过两种途径吸收，即转运蛋白介导的跨细胞途径和被动的细胞旁途径。使用Microchiropteran bat Artibeus literatus（平均质量80.6±3.7 g），我们测试了以下预测：对于相对较少的肠组织，未主动转运的水溶性化合物的吸收将是广泛的，作为一种补偿机制，并且将随着分子量的增加而下降，与筛状旁细胞吸收雅阁。使用标准的药代动力学技术，我们喂食或腹膜内注射代谢惰性碳水化合物L-鼠李糖（分子量= 164 Da）和纤维二糖（分子量= 342 Da），其仅通过细胞旁转运吸收，以及3-O-甲基-D-葡萄糖（3 OMD-葡萄糖），其通过介导（主动）和细胞旁转运吸收。 正如预测的那样，细胞旁探针的生物利用度随着分子量的增加而下降（鼠李糖，90±11%;纤维二糖，10± 3%，n = 8），并且在蝙蝠中的生物利用度显著高于实验室大鼠和其他哺乳动物的生物利用度。 此外，3 OMD-葡萄糖的吸收较高（96±11%）。我们估计，蝙蝠依赖于被动的，细胞旁吸收超过70%的葡萄糖总吸收，远远超过非飞行哺乳动物。虽然可能补偿较少的肠组织，但允许被动吸收的高肠渗透性可能比载体介导的系统对营养吸收的选择性低，并且可能允许毒素从肠腔中的植物和动物材料中吸收。
Bats tend to have less intestinal tissue than comparably sized nonflying mammals. The corresponding reduction in intestinal volume and hence mass of digesta carried is advantageous because the costs of flight increase with load carried and because take-off and maneuverability are diminished at heavier masses. Water soluble compounds, such as glucose and amino acids, are absorbed in the small intestine mainly via two pathways, the transporter-mediated transcellular and the passive, paracellular pathways. Using the microchiropteran bat Artibeus literatus (mean mass 80.6±3.7 g), we tested the predictions that absorption of water-soluble compounds that are not actively transported would be extensive as a compensatory mechanism for relatively less intestinal tissue, and would decline with increasing molecular mass in accord with sieve-like paracellular absorption. Using a standard pharmacokinetic technique, we fed, or injected intraperitonealy the metabolically inert carbohydrates L-rhamnose (molecular mass = 164 Da) and cellobiose (molecular mass = 342 Da) which are absorbed only by paracellular transport, and 3-O-methyl-D-glucose (3OMD-glucose) which is absorbed via both mediated (active) and paracellular transport. As predicted, the bioavailability of paracellular probes declined with increasing molecular mass (rhamnose, 90±11%; cellobiose, 10±3%, n = 8) and was significantly higher in bats than has been reported for laboratory rats and other mammals. In addition, absorption of 3OMD-glucose was high (96±11%). We estimated that the bats rely on passive, paracellular absorption for more than 70% of their total glucose absorption, much more than in non-flying mammals. Although possibly compensating for less intestinal tissue, a high intestinal permeability that permits passive absorption might be less selective than a carrier-mediated system for nutrient absorption and might permit toxins to be absorbed from plant and animal material in the intestinal lumen.
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影响因子：
2.1
作者：
Diamond, J;Bishop, KD;Gilardi, JD
通讯作者：
Gilardi, JD
DOI：
10.1086/639618
发表时间：
1997-05-01
期刊：
PHYSIOLOGICAL ZOOLOGY
影响因子：
--
作者：
Afik, D;McWilliams, SR;Karasov, WH
通讯作者：
Karasov, WH
DOI：
10.1007/s00360-003-0403-3
发表时间：
2004-03-01
影响因子：
2
作者：
Chang, MH;Chediack, JG;Karasov, WH
通讯作者：
Karasov, WH
影响因子：
1.5
作者：
ANDERSON, JH;TAYLOR, AB
通讯作者：
TAYLOR, AB
影响因子：
3.4
作者：
CHANG, RLS;ROBERTSON, CR;BRENNER, BM
通讯作者：
BRENNER, BM