Identified octopaminergic neurons provide an arousal mechanism in the locust brain
Identified octopaminergic neurons provide an arousal mechanism in the locust brain
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DOI：
10.1152/jn.1995.74.6.2739
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发表时间：
1995-12-01
影响因子：
2.5
通讯作者：
Stern, M
中科院分区：
文献类型：
--
作者：
Bacon, JP;Thompson, KSJ;Stern, M
1.习惯化是神经回路（或行为）对重复刺激的反应性下降。不适（或唤醒）可以由突然出现的额外的、新的刺激引起。蝗虫的视觉系统提供了一个明显的唤醒例子：下行对侧运动检测器（DCMD）中间神经元对重复视觉刺激的习惯性反应可以被各种其他视觉和触觉刺激所破坏。章鱼胺应用于蝗虫脑和视叶disabituates DCMD的方式类似的视觉和触觉刺激的效果。蝗虫中枢神经系统包含两对章鱼胺免疫反应细胞，即前脑髓质4（PM 4）神经元，可能潜在地介导这种disabituation效应; PM 4神经元在视叶中树状结构，它们包含章鱼胺，并且它们对disabituate DCMD的相同视觉和触觉刺激作出反应。为了研究PM 4活性是否会使DCMD失去适应性，我们在细胞内记录了一个PM 4神经元，同时在细胞外记录了DCMD。当PM 4神经元被注入超极化电流使其完全失活时，DCMD表现出其对移动视觉刺激的特征性习惯化。然而，去极化PM 4神经元，以产生类似于20 Hz的动作电位，显著增加了每次刺激的DCMD动作电位的数量。因此，PM 4神经元可能发挥重要作用disabitating DCMD新的刺激，这种效果大概是介导的PM 4神经元释放内源性章鱼胺内的视叶。
1. Habituation is the declining responsiveness of a neural circuit (or behavior) to repetitive stimulation. Dishabituation (or arousal) can be brought about by the sudden presentation of an additional, novel stimulus. A clear example of arousal in the locust is provided by the visual system: the habituated response of the descending contralateral movement detector (DCMD) interneuron to repetitive visual stimuli can be dishabituated by a variety of other visual and tactile stimuli.2. Application of octopamine to the locust brain and optic lobes dishabituates the DCMD in a manner similar to the effect of visual and tactile stimulation.3. The locust CNS contains two pairs of octopamine-immunoreactive cells, the protocerebral medulla 4 (PM4) neurons, that could potentially mediate this dishabituation effect; PM4 neurons arborize in the optic lobe, they contain octopamine, and they respond to the same visual and tactile stimuli that dishabituate the DCMD.4. To investigate whether PM4 activity dishabituates the DCMD, we recorded intracellularly from one of the PM4 neurons while recording extracellularly from the DCMD. When the PM4 neuron is injected with hyperpolarizing current to render it completely inactive, the DCMD exhibits its characteristic habituation to a moving visual stimulus. However, depolarizing the PM4 neuron, to produce action potentials at similar to 20 Hz, significantly increases the number of DCMD action potentials per stimulus.5. The PM4 neurons may therefore play an important role in dishabituating the DCMD to novel stimuli; This effect is presumably mediated by PM4 neurons releasing endogenous octopamine within the optic lobe.