Perfusion with cGMP analogue adapts the action potential response of pheromone-sensitive sensilla trichoidea of the hawkmoth Manduca sexta in a daytime-dependent manner
Perfusion with cGMP analogue adapts the action potential response of pheromone-sensitive sensilla trichoidea of the hawkmoth Manduca sexta in a daytime-dependent manner
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DOI：
10.1242/jeb.02432
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发表时间：
2006-10-01
影响因子：
2.8
通讯作者：
Stengl, Monika
中科院分区：
文献类型：
--
作者：
Flecke, Christian;Dolzer, Jan;Stengl, Monika
在不同的蛾类中，依赖信息素的配偶搜索受到严格的昼夜节律控制。但目前尚不清楚雄蛾的外围是否已经发生了白天依赖性的信息素敏感性变化。由于适应信息素刺激会导致夜间活动天蛾 Manduca sexta 的信息素敏感毛状感觉器中环磷酸鸟苷 (cGMP) 的升高，因此我们想确定 cGMP 是否以白天依赖性方式降低嗅觉受体神经元的信息素敏感性。毛状感器的长期尖端记录在清晨（ZT 1-4）进行，此时许多飞蛾仍然活跃，并在中午（ZT 8-11）进行，此时飞蛾正在休息。非适应性信息素刺激方案与用膜可渗透的 cGMP 类似物 8bcGMP 灌注感器淋巴相结合，适应了动作电位反应，但不适应感器电位。 8bcGMP 灌注降低了初始动作电位频率，减少了信息素响应的前 100 毫秒内引发的动作电位数量，并减弱了动作电位幅度的降低。此外，在 ZT 8-11 进行的记录中，8bcGMP 依赖性动作电位频率的下降比在 ZT 1-4 时更强。在一天中的对照记录中，信息素反应变得越来越紧张，而不是阶段性的。仅在 ZT 8-11 时，这种日间依赖性效应通过 8 bcGMP 应用进一步增强。因此，我们假设在飞蛾的休息阶段，cGMP 水平升高是白天依赖性信息素敏感性下降和信息素脉冲时间分辨率下降的基础。
Pheromone-dependent mate search is under strict circadian control in different moth species. But it remains unknown whether daytime-dependent changes in pheromone sensitivity already occur at the periphery in male moths. Because adapting pheromone stimuli cause rises of cyclic guanosine monophosphate (cGMP) in pheromone-sensitive trichoid sensilla of the night-active hawkmoth Manduca sexta, we wanted to determine whether cGMP decreases pheromone-sensitivity of olfactory receptor neurons in a daytime-dependent manner. Long-term tip recordings from trichoid sensilla were performed at the early day (ZT 1-4), when many moths are still active, and at the middle of the day (ZT 8-11), when moths are resting. A non-adapting pheromone-stimulation protocol combined with perfusion of the sensillum lymph with the membrane-permeable cGMP analogue 8bcGMP adapted the action potential response but not the sensillar potential. Perfusion with 8bcGMP decreased the initial action potential frequency, decreased the numbers of action potentials elicited in the first 100 ms of the pheromone response and attenuated the reduction of action potential amplitude. Furthermore, the decrease in 8bcGMP-dependent action potential frequency was stronger in recordings made at ZT 8-11 than at ZT 1-4. In control recordings during the course of the day the pheromone responses became increasingly tonic and less phasic. At ZT 8-11 only, this daytime-dependent effect was further enhanced by 8 bcGMP application. Thus we hypothesize that during the moths' resting phase, elevated cGMP levels underlie a daytime-dependent decrease in pheromone sensitivity and a decline in the temporal resolution of pheromone pulses.