Dando Robin, Pereira Elizabeth, Kurian Mani, Barro-Soria Rene, Chaudhari Nirupa, Roper Stephen D
Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and.
Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and Program in Neuroscience, University of Miami, Miami, Florida.
Am J Physiol Cell Physiol. 2015 Jan 1;308(1):C21-32. doi: 10.1152/ajpcell.00157.2014. Epub 2014 Sep 10.
Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003-1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.
上皮组织的特征是具有特化的细胞间连接，通常定位于细胞的顶端区域。这些连接由相互作用的膜蛋白以及细胞骨架和细胞外基质成分形成。在舌上皮内，紧密连接连接味蕾中味觉感觉细胞的顶端。这些连接构成了一个选择性屏障，限制化学感觉刺激物进入味蕾（Michlig等人，《比较神经学杂志》502:1003 - 1011，2007）。我们测试了化合物渗透到舌上皮感觉终末器官的能力。我们的研究结果揭示了一个围绕味蕾整体的强大屏障，而不仅限于顶端紧密连接。这个屏障阻止许多但不是所有化合物渗透到味蕾中，无论它们是局部应用、注射到舌实质中还是在血液循环中。酶处理表明这个屏障可能包括糖胺聚糖，因为它被软骨素酶破坏，但被蛋白酶破坏的效果较差。用二甲基亚砜（DMSO）短暂处理舌组织样本也可破坏围绕味蕾的屏障。将舌切片短暂暴露于DMSO并不影响切片内味蕾对化学刺激的反应能力。围绕味蕾的高度不可渗透屏障的存在以及突破这一屏障的方法可能与味觉的基础研究和临床治疗相关。
