Social dysfunction is among the core symptoms of schizophrenia. The neuropeptides oxytocin (OXT) and vasopressin (VP) are involved in the regulation of social behaviour and social cognition. There are indications that both of these neurotransmitter systems are altered in schizophrenia. Prenatal (embryonic day 17) exposure to the neurotoxin methylazoxymethanol acetate (MAM; 22 mg/kg) leads to a schizophrenia-like phenotype in rats and has been used as a model of schizophrenia symptoms. Here, we examined the social phenotype of MAM-exposed female and male rats and measured concentrations of OXT, VP and their specific receptors in various brain areas involved in the control of social behaviour. We report decreases in social behaviour and ultrasonic vocalisations (USVs) in the MAM rats during social encounters. Specifically, the duration of social interactions and number of corresponding USVs were reduced in this group. In the MAM rats, "positive" 50-kHz USVs were flatter, i.e., displayed lower bandwidth, a greater percentage of "short" calls and lower percentage of frequency-modulated calls. The MAM animals exhibited diminished interest towards social stimuli in olfactory preference tests. In the resident-intruder test, MAM exposure reduced dominance behaviour only in the males. We also report cognitive impairments, including reduced novel object recognition and cognitive inflexibility in the attentional set shifting test, and decreased OXT and OXT receptor concentrations in the prefrontal cortex and hypothalamus and VP and VP receptors in the hypothalamus in the MAM rats. Deficits in central OXT and VP systems may underlie abnormalities present in the MAM model of schizophrenia.

中文翻译：

---

雄性和雌性大鼠精神分裂症神经发育模型中的社会功能障碍：行为和生化研究。

社会功能障碍是精神分裂症的核心症状之一。神经肽催产素（OXT）和加压素（VP）参与社会行为和社会认知的调节。有迹象表明，这两种神经递质系统在精神分裂症中均发生了改变。产前（胚胎第17天）暴露于神经毒素甲基乙酸甲酯（MAM； 22 mg / kg）会在大鼠中导致精神分裂症样表型，并已被用作精神分裂症症状的模型。在这里，我们检查了暴露于MAM的雌性和雄性大鼠的社会表型，并测量了参与控制社会行为的各个大脑区域的OXT，VP及其特定受体的浓度。我们报告减少了社交场合中MAM大鼠的社交行为和超声波发声（USV）。特别，该组的社交互动持续时间和相应的USV数量都减少了。在MAM大鼠中，“正” 50 kHz USV比较平坦，即显示较低的带宽，较大的“短”呼叫百分比和较低的频率调制呼叫百分比。在嗅觉偏好测试中，MAM动物对社交刺激的兴趣减弱。在常驻入侵者测试中，MAM暴露仅在男性中降低了主导行为。我们还报告了认知障碍，包括在注意力集中转移测试中减少了新物体识别和认知僵硬，并降低了MAM大鼠前额叶皮层和下丘脑的OXT和OXT受体浓度以及下丘脑的VP和VP受体。