Saifullah A S M, Page Terry L
Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA.
J Biol Rhythms. 2009 Apr;24(2):144-52. doi: 10.1177/0748730408331166.
In the cockroach, olfactory sensitivity as measured by the amplitude of the electroantennogram (EAG) is regulated by the circadian system. We wished to determine how this rhythm in antennal response was reflected in the activity of individual olfactory receptor neurons. The amplitude of the EAG and the activity of olfactory receptor neurons (ORNs) in single olfactory sensilla were recorded simultaneously for 3 to 5 days in constant darkness from an antenna of the cockroach Leucophaea maderae. Both EAG amplitude and the spike frequency of the ORNs exhibited circadian rhythms with peak amplitude/activity occurring in the subjective day. The phases of the rhythms were dependent on the phase of the prior light cycle and thus were entrainable by light. Ablation of the optic lobes abolished the rhythm in EAG amplitude as has been previously reported. In contrast, the rhythm in ORN response persisted following surgery. These results indicated that a circadian clock outside the optic lobes can regulate the responses of olfactory receptor neurons and further that this modulation of the ORN response is not dependent on the circadian rhythm in EAG amplitude.
在蟑螂中，通过触角电图（EAG）振幅测量的嗅觉敏感性受昼夜节律系统调节。我们希望确定触角反应中的这种节律如何在单个嗅觉受体神经元的活动中体现出来。在持续黑暗的条件下，从马德拉蜚蠊的触角上同时记录单个嗅觉感受器中EAG的振幅和嗅觉受体神经元（ORN）的活动，持续3至5天。EAG振幅和ORN的放电频率均呈现昼夜节律，峰值振幅/活动出现在主观白天。这些节律的相位取决于先前光周期的相位，因此可被光诱导。如先前报道的那样，切除视叶消除了EAG振幅的节律。相比之下，ORN反应的节律在手术后仍然存在。这些结果表明，视叶外的昼夜节律时钟可以调节嗅觉受体神经元的反应，并且进一步表明ORN反应的这种调节不依赖于EAG振幅的昼夜节律。
