Unidad Periférica Xalapa, Instituto de Investigaciones Biomédicas, Universidad Nacional Xalapa, México.
Neuropsychobiology. 2012;66(3):167-73. doi: 10.1159/000339946. Epub 2012 Aug 29.
Wistar rats subjected to physical stress release a urine alarm pheromone (2-heptanone) that produces signs of anxiety and despair in receptor rats not subjected to physical stress. However, unknown are the effects of 2-heptanone on the firing rate of the basal amygdala, a structure that participates in the expression of fear, and the participation of anterior olfactory epithelial organs, namely the septal organ and vomeronasal organ (SO-VNO). We explored the effects of 2-heptanone applied near the nostrils on single-unit extracellular recordings from the basal amygdala in a sham-operated group and rats that underwent removal of the SO-VNO. The firing rate of basal amygdala neurons in the SO-VNO removal group was significantly higher than in the sham-operated group. In both groups, recordings were classified according to the responses to 2-heptanone (i.e., increased firing rate, decreased firing rate, and no response). SO-VNO removal was associated with an increased firing rate in the three types of neurons. A similar number of neurons increased their firing rate during and after 2-heptanone stimulation in both groups, but such an increase in firing rate was longer in the group of rats subjected to SO-VNO removal. The results indicate that the SO-VNO is not essential for the effect of 2-heptanone on the firing rate of basal amygdala neurons. SO-VNO ablation did not block but rather accentuated the response of amygdala neurons to 2-heptanone.
遭受身体应激的 Wistar 大鼠会释放尿液警报信息素（2-庚酮），这种信息素会在未遭受身体应激的受体大鼠中产生焦虑和绝望的迹象。然而，目前尚不清楚 2-庚酮对基底杏仁核的放电率的影响，基底杏仁核是参与恐惧表达的结构，以及前嗅上皮器官（即隔器官和犁鼻器）的参与。我们探索了在假手术组和去除 SO-VNO 的大鼠中，将 2-庚酮施加到鼻子附近对基底杏仁核的单细胞外记录的影响。在 SO-VNO 去除组中，基底杏仁核神经元的放电率明显高于假手术组。在这两个组中，根据对 2-庚酮的反应（即放电率增加、放电率降低和无反应）对记录进行分类。在这两种类型的神经元中，SO-VNO 的去除与放电率的增加有关。在两组中，有相同数量的神经元在 2-庚酮刺激期间和之后增加了其放电率，但在经历 SO-VNO 去除的大鼠组中，这种放电率的增加持续时间更长。结果表明，SO-VNO 对于 2-庚酮对基底杏仁核神经元放电率的影响并非必需。SO-VNO 消融没有阻断，而是增强了杏仁核神经元对 2-庚酮的反应。
