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Mechanisms of bitter taste reception

苦味接收机制

基本信息

批准号：
11480247
负责人：
KANEKO Akimichi
金额：
$ 9.34万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11480247/
关键词：
toungue taste receptor cell bitter sensation Calcium ion quinine patch clamp noise analysis power spectrum distribution 苦み単一チャネル記録チャネル電導度カエル苦味 Na電流 K電流電気的結合茸状乳頭味壺

项目摘要

Mechanisms of taste transduction in gustatory receptor cells are not well described. One reason is that most of the past studies have been carried out on isolated taste receptor cells, in which identification of cell types and the cell location are unidentifiable. In the present study we developed a technique to making a slice preparation of the bullfrog fungi form papilla. Voltage-gated ionic current and the response to quinine were studied on the four types of morphologically identified taste cells by whole-cell patch clamp recording with Lucifer yellow-filled pipette. Dye-coupled type la cells (mucous cells) did not show voltage-activated currents. Type Ib cells (wing cells), type II cells (rod cells) and type III cells had voltage-gated sodium (I_<Na>) and potassium currents (I_K) and generated action potentials. The amplitude of Nawas significantly larger in type Ib and II cells than in type III cells. Type Ib and II cells responded to quinine but Type III cells did not.We also studied the cation current from the frog taste receptor cell activated by quinine. From the variance/mean ratio of the quinine-activated current, the single-channel conductance was estimated to be 12 pS in zero extracellular Ca^<2+>. In the presence of 1.8 mM Ca^<2+>, this conductance decreased to 5 pS. The dependence of the current on quinine concentration had a K_<1/2> of 0.48 mM in the absence of extracellular Ca^<2+>, which increased to 2.8 mM in 1.8 mM external Ca^<2+>. The spectral power density distribution of the quinine-activated current could be described by the sum of two Lorentzian functions, with corner frequencies not substantially different in the absence and presence of 1.8 mM external Ca^<2+>. The above results support the notion that the major component of the response of frog taste receptor cells to quinine comes from an ion channel directly activated by quinine.

味觉感受器细胞中味觉转导的机制尚不清楚。一个原因是，过去的大多数研究都是在分离的味觉受体细胞上进行的，其中细胞类型和细胞位置的识别是无法识别的。在本研究中，我们开发了牛蛙乳突真菌的切片制备技术。采用路西法黄填充移液管全细胞膜片钳记录技术，研究了电压门控离子电流和奎宁对四种形态鉴定的味觉细胞的响应。染料偶联型la细胞（黏液细胞）不显示电压激活电流。Ib型细胞（翼细胞）、II型细胞（杆状细胞）和III型细胞具有电压门控的钠电流（I_<Na>）和钾电流（I_K），并产生动作电位。在Ib和II型细胞中na的振幅明显大于III型细胞。Ib和II型细胞对奎宁有应答，而III型细胞对奎宁无应答。我们还研究了奎宁激活青蛙味觉感受器细胞的阳离子电流。根据奎宁激活电流的方差/平均值，估计在零细胞外Ca^<2+>时，单通道电导为12 pS。在没有Ca^<2+>的情况下，电流对奎宁浓度的依赖性K_<1/2>为0.48 mM，在1.8 mM Ca^<2+>的情况下，K_<1/2>增加到2.8 mM。奎宁激活电流的频谱功率密度分布可以用两个洛伦兹函数的和来描述，在没有和存在1.8 mM外部Ca^<2+>的情况下，角频率没有显著差异。上述结果支持了青蛙味觉受体细胞对奎宁反应的主要成分来自奎宁直接激活的离子通道的观点。