Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama, Japan.
Pflugers Arch. 2021 Jan;473(1):3-13. doi: 10.1007/s00424-020-02464-4. Epub 2020 Sep 16.
The variety of taste sensations, including sweet, umami, bitter, sour, and salty, arises from diverse taste cells, each of which expresses specific taste sensor molecules and associated components for downstream signal transduction cascades. Recent years have witnessed major advances in our understanding of the molecular mechanisms underlying transduction of basic tastes in taste buds, including the identification of the bona fide sour sensor H channel OTOP1, and elucidation of transduction of the amiloride-sensitive component of salty taste (the taste of sodium) and the TAS1R-independent component of sweet taste (the taste of sugar). Studies have also discovered an unconventional chemical synapse termed "channel synapse" which employs an action potential-activated CALHM1/3 ion channel instead of exocytosis of synaptic vesicles as the conduit for neurotransmitter release that links taste cells to afferent neurons. New images of the channel synapse and determinations of the structures of CALHM channels have provided structural and functional insights into this unique synapse. In this review, we discuss the current view of taste transduction and neurotransmission with emphasis on recent advances in the field.
味觉的多样性，包括甜、鲜、苦、酸和咸，源于不同的味觉细胞，每个味觉细胞都表达特定的味觉传感器分子和相关成分，用于下游信号转导级联。近年来，我们对味蕾中基本味觉转导的分子机制有了更深入的了解，包括鉴定出真正的酸味传感器 H 通道 OTOP1，阐明了咸味（钠离子的味道）和甜味（糖的味道）中阿米洛利敏感成分的转导。研究还发现了一种非常规的化学突触，称为“通道突触”，它使用动作电位激活的 CALHM1/3 离子通道，而不是突触小泡的胞吐作用作为神经递质释放的通道，将味觉细胞与传入神经元连接起来。通道突触的新图像和 CALHM 通道的结构确定为这个独特的突触提供了结构和功能上的见解。在这篇综述中，我们讨论了味觉转导和神经传递的当前观点，重点介绍了该领域的最新进展。
