Sato Taku, Suzuki Eiji, Yokoyama Masamoto, Watanabe Shigeru, Miyaoka Hitoshi
Department of Psychiatry, Kitasato University School of Medicine, Sagamihara, Japan.
Neuropsychobiology. 2006;53(3):142-7. doi: 10.1159/000093100. Epub 2006 May 4.
The conditioned fear response is considered to be acquired by experimental animals when tone information is combined with that of an electrical foot shock (unconditioned stimulus) in the amygdala. Nitric oxide biosynthesized in the brain is reportedly involved in several kinds of learning.
In this study, we continuously monitored the NO(3)(-) level, as a marker of nitric oxide production, in the amygdala starting before the application of tone and electrical foot shock stimuli together (conditioned group) or the tone stimulus alone (control group) on day 1, until after the tone information was given (both groups) on day 2, using the in vivo microdialysis method.
The NO(3)(-) level of the conditioned group was increased on both day 1 and day 2, while that of the control group was not elevated on either day. Freezing behavior was observed in the conditioned but not the control rats.
Although the sources of NO(3)(-) remain uncertain, these results suggest that nitric oxide is associated with auditory fear conditioning and the response to a conditioned stimulus.
当音调信息与电足部电击（非条件刺激）在杏仁核中结合时，实验动物被认为会习得条件性恐惧反应。据报道，大脑中生物合成的一氧化氮参与多种学习过程。
在本研究中，我们使用体内微透析方法，在第1天音调与电足部电击刺激（条件组）或单独音调刺激（对照组）一起施加之前开始，持续监测杏仁核中作为一氧化氮产生标志物的NO(3)(-)水平，直到第2天给予音调信息后（两组）。
条件组的NO(3)(-)水平在第1天和第2天都升高，而对照组在任何一天都没有升高。在条件组大鼠中观察到僵住行为，而对照组大鼠未观察到。
尽管NO(3)(-)的来源尚不确定，但这些结果表明一氧化氮与听觉恐惧条件反射及对条件刺激的反应有关。
