MOLECULAR-BIOLOGY OF SMELL - EXPRESSION OF THE MULTIGENE FAMILY ENCODING PUTATIVE ODORANT RECEPTORS
MOLECULAR-BIOLOGY OF SMELL - EXPRESSION OF THE MULTIGENE FAMILY ENCODING PUTATIVE ODORANT RECEPTORS
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DOI：
10.1101/sqb.1992.057.01.056
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发表时间：
1992-01-01
期刊：
影响因子：
--
通讯作者：
NGAI, J
中科院分区：
文献类型：
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作者：
CHESS, A;BUCK, L;NGAI, J
环境刺激由感觉神经元识别，并且该信息被传输到大脑，在那里它被解码以提供外部世界的内部表示。脊椎动物的嗅觉系统可以识别和区分大量不同分子结构的气味物质。例如，人类能够区分成千上万种不同的气味。虽然气味物质通常表现出广泛不同的结构，但分子结构的细微变化可能导致感知气味的显著差异。嗅觉神经元如何识别我们定义为气味的大量分子结构？不同气味的检测可能是由于嗅觉神经元上的气味配体与特定受体的关联。嗅觉感知可能涉及少量的气味受体，每一个都能够与大量的气味相互作用。或者，大量的受体可以与一种或少量的气味剂结合。因此，嗅觉感知在识别多种可能的配体方面提出了问题，这也是在包括免疫系统在内的其他生物系统中遇到的问题。然而，与免疫系统不同的是，嗅觉系统需要大脑区分哪些受体已经被激活，以识别不同的气味刺激。嗅觉感知是通过气味与鼻腔后部感觉细胞上的受体相互作用而启动的。这些嗅觉感觉神经元是双极的：一个特化的树突终止于粘膜表面的纤毛集合，一个轴突直接延伸到大脑，在那里它与嗅球中的细胞形成突触，这是大脑中的第一个中继（有关综述，参见Lancet 1986; Shepherd 1991）。气味剂与嗅觉纤毛上的特异性受体相互作用，导致细胞内第二信使cAMP或三磷酸肌醇（IP 3）的快速和短暂升高（Pace et al. 1985; Sklar et al. 1986; Boekhoff et al. 1990; Breer et al. 1990）。cAMP的升高被认为直接激活环核苷酸门控阳离子通道（中村和Gold 1987; Dhallan等人1990; Goulding等人1992），导致膜去极化和动作电位的产生，这些动作电位沿沿着感觉轴突传播到大脑。以这种方式，气味诱发的cAMP升高被转换成嗅觉神经元中的电信号。虽然IP 3敏感
Environmental stimuli are recognized by sensory neurons, and this information is transmitted to the brain where it is decoded to provide an internal representation of the external world. The olfactory sensory system of vertebrates can recognize and discriminate a large number of odorants of diverse molecular structure. Humans, for example, are capable of distinguishing among thousands of distinct odors. Although odorants often exhibit widely different structures, subtle changes in molecular structure can lead to striking differences in perceived odor. How do olfactory sensory neurons recognize the vast array of molecular structures that we define as odorants? The detection of distinct odorants presumably results from the association of odorous ligands with specific receptors on olfactory neurons. Olfactory perception may involve a small number of odorant receptors, each capable of interacting with a large number of odorants. Alternatively, a large number of receptors may associate with one or a small number of odorants. Olfactory perception therefore poses a problem in the recognition of multiple possible ligands, a problem also encountered in other biological systems, including the immune system. Unlike the immune system, however, the olfactory sensory system requires that the brain distinguish which receptors have been activated in order to identify different odorant stimuli.Olfactory perception is initiated by the interaction of odors with receptors on sensory cells that line the posterior portion of the nasal cavity. These olfactory sensory neurons are bipolar: A specialized dendrite terminates in a collection of cilia on the mucosal surface, and an axon extends directly to the brain where it synapses on cells in the olfactory bulb, the first relay in the brain (for reviews, see Lancet 1986; Shepherd 1991). Odorants interact with specific receptors on olfactory cilia, leading to rapid and transient elevations in the intracellular second messengers, cAMP, or inositol triphosphate (IP3)(Pace et al. 1985; Sklar et al. 1986; Boekhoff et al. 1990; Breer et al. 1990). Elevations in cAMP are thought to directly activate a cyclic nucleotide-gated cation channel (Nakamura and Gold 1987; Dhallan et al. 1990; Goulding et al. 1992), resulting in membrane depolarization and the generation of action potentials which are propagated along the sensory axon to the brain. In this manner, odorant-evoked elevations in cAMP are transduced into electrical signals in olfactory neurons. Although an IP3-sensitive