Postnatal development of membrane excitability in taste cells of the mouse vallate papilla
Postnatal development of membrane excitability in taste cells of the mouse vallate papilla
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DOI：
10.1523/jneurosci.22-02-00493.2002
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发表时间：
2002-01-15
影响因子：
5.3
通讯作者：
Pietra, P
中科院分区：
文献类型：
--
作者：
Bigiani, A;Cristiani, R;Pietra, P
哺乳动物的外周味觉系统在出生后的发育过程中经历了功能性的变化。这些变化可能反映了味觉细胞膜特性的年龄依赖性改变，味觉细胞使用大量的离子通道进行转导机制。然而，很少的信息是可用的膜事件在发展中的味觉细胞。我们已经解决了这个问题，通过研究电压依赖性Na+，K+，和Cl-电流（I-Na，I-K，和I-Cl，分别）在一个子集的味觉细胞（所谓的“Na/OUT”细胞，这是电兴奋，被认为是感觉）从小鼠的乳头状突起。电压依赖性电流在味觉信号转导过程中起着关键作用，尤其是在动作电位的产生中。膜片钳记录显示，I-Na，I-K和I-Cl在出生后发育的早期表达。然而，只有I-K和I-Cl密度在发育中的Na/OUT细胞中显著增加。与I-K密度的增加相一致，我们发现动作电位波形明显改变，复极速度增加，伴随着重复放电能力的增强。除了膜兴奋性的变化，在假定的感觉细胞，我们观察到了伴随的增加，在发生的胶质样味细胞（所谓的“漏”细胞）之间的修补细胞。渗漏细胞可能参与消散化学感受细胞动作电位放电过程中细胞外K+的增加。因此，发育中的味觉细胞的小鼠乳头状突起经历了一个显着的电生理成熟和多样化。这些功能变化可能对发育过程中味蕾的转导能力产生深远的影响。
The mammalian peripheral taste system undergoes functional changes during postnatal development. These changes could reflect age-dependent alterations in the membrane properties of taste cells, which use a vast array of ion channels for transduction mechanisms. Yet, scarce information is available on the membrane events in developing taste cells. We have addressed this issue by studying voltage-dependent Na+, K+, and Cl- currents (I-Na, I-K, and I-Cl, respectively) in a subset of taste cells (the so-called "Na/OUT" cells, which are electrically excitable and thought to be sensory) from mouse vallate papilla. Voltage-dependent currents play a key role during taste transduction, especially in the generation of action potentials. Patch-clamp recordings revealed that I-Na, I-K, and I-Cl were expressed early in postnatal development. However, only I-K and I-Cl densities increased significantly in developing Na/OUT cells. Consistent with the rise of I-K density, we found that action potential waveform changed markedly, with an increased speed of repolarization that was accompanied by an enhanced capability of repetitive firing. In addition to membrane excitability changes in putative sensory cells, we observed a concomitant increase in the occurrence of glia-like taste cells (the so called "leaky" cells) among patched cells. Leaky cells are likely involved in dissipating the increase of extracellular K+ during action potential discharge in chemosensory cells. Thus, developing taste cells of the mouse vallate papilla undergo a significant electrophysiological maturation and diversification. These functional changes may have a profound impact on the transduction capabilities of taste buds during development.