Spike amplitude of single-unit responses in antennal sensillae is controlled by the Drosophila circadian clock
Spike amplitude of single-unit responses in antennal sensillae is controlled by the Drosophila circadian clock
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DOI：
10.1016/j.cub.2008.04.060
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发表时间：
2008-06-03
期刊：
影响因子：
9.2
通讯作者：
Hardin, Paul E.
中科院分区：
文献类型：
--
作者：
Krishnan, Parthasarathy;Chatterjee, Abhishek;Hardin, Paul E.
在微生物系统[1]、无脊椎动物[2-5]和哺乳动物[6]中观察到膜电位和自发放电频率的昼夜节律变化。果蝇嗅觉感觉神经元（OSN）中的振荡器对于维持EAG反应中的节律是必要且足够的[7，8]，这表明气味受体（OR）和/或OR依赖性过程受时钟控制。我们测量了野生型，时钟突变体，气味受体突变体和G蛋白偶联受体激酶2（Gprk 2）突变体苍蝇的不同触角感觉器的单单位反应，以研究驱动嗅觉节律的细胞和分子机制。自发尖峰振幅，但不是自发或气味诱导的放电频率，是在时钟控制下，在ab 1和ab 3 basiconic感觉器和T2的tuberoid感觉器。树突中缺乏气味受体的突变体显示恒定的低尖峰振幅，并且OSN中GPRK 2水平的降低或增加分别导致恒定的低或恒定的高自发尖峰振幅。我们的结论是，尖峰幅度控制的生物钟在basiconic和mesidic感觉器，并需要GPRK 2的表达和树突中的功能OR的存在。这些结果表明，GPRK 2水平的节律控制OR定位和OR依赖性离子通道活性和/或组成，以介导自发峰电位振幅的节律。
Circadian changes in membrane potential and spontaneous firing frequency have been observed in microbial systems [1], invertebrates [2-5], and mammals [6]. Oscillators in olfactory sensory neurons (OSNs) from Drosophila are both necessary and sufficient to sustain rhythms in electroanntenogram (EAG) responses [7, 8], suggesting that odorant receptors (ORs) and/or OR-dependent processes are under clock control. We measured single-unit responses in different antennal sensillae from wild-type, clock mutant, odorant-receptor mutant, and G protein-coupled receptor kinase 2 (Gprk2) mutant flies to examine the cellular and molecular mechanisms that drive rhythms in olfaction. Spontaneous spike amplitude, but not spontaneous or odor-induced firing frequency, is under clock control in ab1 and ab3 basiconic sensillae and T2 trichoid sensillae. Mutants lacking odorant receptors in dendrites display constant low spike amplitudes, and the reduction or increase of levels of GPRK2 in OSNs results in constant low or constant high spontaneous spike amplitudes, respectively. We conclude that spike amplitude is controlled by circadian clocks in basiconic and trichoid sensillae and requires GPRK2 expression and the presence of functional ORs in dendrites. These results argue that rhythms in GPRK2 levels control OR localization and OR-dependent ion channel activity and/or composition to mediate rhythms in spontaneous spike amplitude.