Program in Neuroscience and Department of Biological Sciences, Florida State University, Tallahassee, FL 32306-4295, USA.
Neuroscience. 2011 Apr 28;180:96-104. doi: 10.1016/j.neuroscience.2011.02.030. Epub 2011 Feb 17.
The male mouse medial amygdala is an important site for integration of main and accessory olfactory information. Exposure to biologically relevant chemical signals from the same species (conspecific) results in a general pattern of immediate early gene (IEG) expression in medial amygdala different from that elicited by chemical signals from other species (heterospecific), of no demonstrable biological relevance. The neuropeptide oxytocin (OT) in the medial amygdala has been shown to be necessary for social recognition. In the present set of experiments, male mice with i.c.v. cannulae were injected with either PBS (vehicle control) or oxytocin antagonist (OTA) (1 ng in 1 μl PBS) and exposed to conspecific (female mouse urine) and heterospecific (steer urine and worn cat collar) chemical stimuli. Similarly to our previous report with intact male mice [Samuelsen and Meredith (2009a) Brain Res 1263:33-42], PBS-injected mice exhibited different immediate early gene (IEG) expression patterns in the medial amygdala according to the biological relevance of the chemical stimuli. However, OTA injection eliminates the increase in IEG expression in the medial amygdala to any of the tested conspecific or heterospecific stimuli. Importantly, OTA injection disrupts avoidance of an unfamiliar predator odor, worn cat collar. Here we suggest that the disruption of social recognition behavior in male mice with altered OT receptor activity results from an inability of the medial amygdala to process relevant conspecific (and heterospecific) chemosensory signals.
雄性老鼠的内侧杏仁核是整合主要和辅助嗅觉信息的重要部位。暴露于来自同一物种（同物种）的具有生物相关性的化学信号会导致内侧杏仁核中即时早期基因（IEG）表达的一般模式与来自其他物种（异物种）的化学信号引起的模式不同，而没有表现出明显的生物学相关性。内侧杏仁核中的神经肽催产素（OT）已被证明对于社会识别是必要的。在这组实验中，具有脑室内套管的雄性老鼠被注射了 PBS（载体对照）或催产素拮抗剂（OTA）（1ng 在 1μlPBS 中），并暴露于同物种（雌性老鼠尿液）和异物种（公牛尿液和磨损的猫项圈）化学刺激物。与我们之前对完整雄性老鼠的报告类似[Samuelsen 和 Meredith（2009a）Brain Res 1263:33-42]，PBS 注射的老鼠根据化学刺激物的生物相关性表现出内侧杏仁核中不同的即时早期基因（IEG）表达模式。然而，OTA 注射消除了内侧杏仁核对任何测试的同物种或异物种刺激物的 IEG 表达增加。重要的是，OTA 注射破坏了对陌生捕食者气味（磨损的猫项圈）的回避。在这里，我们建议改变 OT 受体活性的雄性老鼠的社会识别行为的破坏是由于内侧杏仁核无法处理相关的同物种（和异物种）化学感觉信号。
