Cyclic Nucleotide-Sensitive Ion Channels In Olfactory Receptor Cell Membrane.

嗅觉受体细胞膜中的环状核苷酸敏感离子通道。

• 批准号: 63540557
• 负责人: SUZUKI Noriyo
• 金额: $ 1.22万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63540557/
• 关键词: Olfactory Transduction Mechanism; Cyclic Nucleotide-Sensitive Ion channels; Dynamics of Ion Channel Activity; Cation Selectivity; Unit Conductance; Cation Channels; Purification of Olfactory Cilia; Ion Channel Protein; 嗅受容機構; 細胞内伝達; 環状ヌクレオチド感受性イ

It has been proposed that an adenylate or guanylate cyclase cascade is involved in coupling odorant-activation of olfactory receptor molecule with conductance changes, giving rise to olfactory receptor potentials. Cyclic nucleotides have been thought to act on the conductance as intracellular messengers. Although the odorant-activation of adenylate cyclase has been examined extensively, molecular nature of the proteins in the cascade and the mechanism how these as a whole regulate the conductance have not been fully understood. We have focused on the studies on electrical properties and molecular nature of the cyclic nucleotide-activated ion channels, and have found that the channels have the following characteristics: (1)The channels are activated directly by both cyclic AMP and cyclic GMP. This indicates that the phosphorlylation of channel molecule is not required in its activation. There is a possibility whether olfactory adenylate cyclase is not a single species of enzyme or does … More not have a substrate specificity for production of different cyclic nucleotides. (2)The channels have a low cationic selectivity. Many monovalent and divalent cations can pass through the channels. Thus, the channels may be categorized into a species of the "cation channels". (3)The channel molecule has at least two cooperative binding sites for the cyclic nucleotides and their affinity (K_<1/2>) to the cyclic nucleotides ranges between 3 and 5 uM. (4)The channels have a unit conductance of 24 pS. The distribution of channel open times is expressed as a sum of two exponentials. The time constants are 10.1 msec and 0.9 msec at 1 uM cAMP. The channels are blocked by divalent cations likely in a voltage-dependent manner. This raises the possibility that divalent cations play roles in the adaptation process through whether their direct blockage of the channels or their activation or inhibition of phosphodiesterase dr adenylate cyclase activity. (5)The channels are distributed in not only olfactory cilia but also dendrite and soma membrane. (6)The candidate channel molecule is a protein with a molecular mass of 35-39 kDa. Less

已经提出，腺苷酸或鸟苷酸环化酶级联参与嗅觉受体分子的气味激活与电导变化的偶联，从而引起嗅觉受体电位。环核苷酸被认为是细胞内的信使，对电导起作用。虽然腺苷酸环化酶的气味激活已被广泛研究，级联中的蛋白质的分子性质和这些作为一个整体如何调节电导的机制尚未完全理解。我们对环核苷酸激活离子通道的电学性质和分子本质进行了研究，发现环核苷酸激活离子通道具有以下特点：（1）通道直接被环腺苷酸（cAMP）和环鸟苷酸（cGMP）激活;这表明通道分子的磷酸化在其激活中不是必需的。嗅觉腺苷酸环化酶有可能不是一种单一的酶， ...更多信息 不具有生产不同环核苷酸的底物特异性。（2）通道的阳离子选择性较低。许多一价和二价阳离子可以通过通道。因此，通道可以被分类为“阳离子通道”的种类。（3）通道分子至少有两个与环核苷酸协同结合的位点，其亲和力（K_（1/2））在3 ~ 5 μ M之间。（4）通道的单位电导为24 pS。通道开放时间的分布表示为两个指数的和。在1 μ M cAMP时，时间常数为10.1 msec和0.9 msec。二价阳离子可能以电压依赖性方式阻断通道。这就提出了二价阳离子在适应过程中发挥作用的可能性，无论是通过它们直接阻断通道还是激活或抑制磷酸二酯酶或腺苷酸环化酶活性。（5）通道不仅分布在嗅纤毛上，而且也分布在树突和索马膜上。（6）候选通道分子是分子量为35-39 kDa的蛋白质。少

项目成果

Suzuki,N.: Proc.Jap.Symp.Taste ＆ Smell. 22. 189-192 (1988)

铃木，N.：Proc.Jap.Symp.味觉与嗅觉。22. 189-192 (1988)

Suzuki,N.(Ed.I.J.Miller,Jr.): "Cyclic nucleotide-induced conductance increase in solitary olfactory receptor cells.In:The Beidler Symposium On Taste And Smell" Book Service Assoc.,Inc.Winston-Salemn, 8 (1988)

Suzuki,N.（Ed.I.J.Miller,Jr.）：“单独嗅觉受体细胞中环核苷酸诱导的电导增加。见：贝德勒味觉和嗅觉研讨会”图书服务协会，Inc.Winston-Salemn，8（

Suzuki,N.: "Properties of single cyclic nucleotide-activated ion channels in the olfactory receptor soma membrane." Proc.Jap.Symp.Taste & Smell. 23. 71-74 (1989)

Suzuki,N.：“嗅觉受体体膜中单环核苷酸激活离子通道的特性。”

篠沢隆雄: 生物物理. 28. 38-41 (1988)

筱泽隆夫：生物物理学。28。38-41（1988）

Suzuki,N.: Chemical Senses. 13. 311 (1988)

铃木，N.：化学感官。