Action Potential-Enhanced ATP Release From Taste Cells Through Hemichannels
Action Potential-Enhanced ATP Release From Taste Cells Through Hemichannels
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DOI：
10.1152/jn.00414.2010
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发表时间：
2010-08-01
影响因子：
2.5
通讯作者：
Ninomiya, Yuzo
中科院分区：
文献类型：
--
作者：
Murata, Yoshihiro;Yasuo, Toshiaki;Ninomiya, Yuzo
Yumata Y，Yasuo T，Yoshida R，Obata K，Yanagawa Y，MarGolskee RF，Ninomiya Y。动作电位--促进味觉细胞通过半脑沟释放ATP。神经生理学杂志104：896-901,2010。2010年6月2日首次出版；DOI：10.1152/jn.00414.2010。只有一些味觉细胞会对智者刺激产生动作电位。II型味觉细胞表达许多味觉传导分子，但缺乏精心设计的突触，这让人对这些细胞中动作电位的功能意义产生了疑问。我们研究了味觉细胞释放三磷酸腺苷(ATP)递质对动作电位的依赖性。为了鉴定II型味觉细胞，我们使用了表达来自α-味觉蛋白启动子的绿色荧光蛋白(GFP)转基因的小鼠。动作电位由基面连接到单个GFP阳性味觉细胞的电极记录。我们通过在味觉刺激动作电位后立即收集电极溶液并使用荧光素酶测定ATP的方法来监测表达味觉蛋白的味觉细胞的ATP释放。在顶膜上用糖精、奎宁或谷氨酸刺激表达味觉蛋白的味觉细胞可增加电极溶液中的三磷酸腺苷水平；三磷酸腺苷的量取决于放电速率。自发放电频率的增加也诱导了味觉细胞中表达味觉蛋白的ATP释放。表达味觉蛋白的味觉细胞的ATP释放被河豚毒素抑制，并被甘草酮抑制到检测下限以下。我们的数据支持这一假设，即味觉细胞对甜、苦或鲜味做出反应的动作电位通过pannin 1而不是基于连接蛋白的半通道来促进ATP的释放。
Murata Y, Yasuo T, Yoshida R, Obata K, Yanagawa Y, Margolskee RF, Ninomiya Y. Action potential-enhanced ATP release from taste cells through hemichannels. J Neurophysiol 104: 896-901, 2010. First published June 2, 2010; doi: 10.1152/jn.00414.2010. Only some taste cells fire action potentials in response to sapid stimuli. Type II taste cells express many taste transduction molecules but lack well-elaborated synapses, bringing into question the functional significance of action potentials in these cells. We examined the dependence of adenosine triphosphate (ATP) transmitter release from taste cells on action potentials. To identify type II taste cells we used mice expressing a green fluorescence protein (GFP) transgene from the alpha-gustducin promoter. Action potentials were recorded by an electrode basolaterally attached to a single GFP-positive taste cell. We monitored ATP release from gustducin-expressing taste cells by collecting the electrode solution immediately after tastant-stimulated action potentials and using a luciferase assay to quantify ATP. Stimulation of gustducin-expressing taste cells with saccharin, quinine, or glutamate on the apical membrane increased ATP levels in the electrode solution; the amount of ATP depended on the firing rate. Increased spontaneous firing rates also induced ATP release from gustducin-expressing taste cells. ATP release from gustducin-expressing taste cells was depressed by tetrodotoxin and inhibited below the detection limit by carbenoxolone. Our data support the hypothesis that action potentials in taste cells responsive to sweet, bitter, or umami tastants enhance ATP release through pannexin 1, not connexin-based hemichannels.