McCarthy M M
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201, USA.
Adv Exp Med Biol. 1995;395:235-45.
Establishment of the behavioral significance of oxytocin neurotransmission in the brain has been a leading component in the emerging concept of neuropeptide regulation of behavior. Elucidating the behavioral effects of oxytocin has been facilitated by its profound regulation by estrogen in discrete brain areas and its subsequent role in estrogen-dependent responses. For example, female sexual behavior is estrogen dependent, estrogen markedly increases oxytocin binding in the ventromedial nucleus of the hypothalamus and infusion of oxytocin in this brain area increases female sexual behavior. A similar correlation exists for the role of oxytocin and estrogen in the regulation of maternal behavior. A possible underlying cause of these behavioral effects is that by acting as an anxiolytic, oxytocin reduces the inhibition inherent in social encounters. Behavioral tests in the laboratory frequently involve the exposure of the animal to a novel environment, such as a pup-retrieval apparatus or mating arena, combined with exposure to an unfamiliar conspecific. These stimuli are likely to induce a stress response and perhaps this anxiety is reduced by oxytocin. Recent evidence in mice suggests that oxytocin has anxiolytic properties in estrogen-treated females (McCarthy and Goldman, 1994) and supports the hypothesis that a unifying principal in oxytocin action in the brain is to facilitate social encounters by reducing the associated anxiety.
确定大脑中催产素神经传递的行为意义，一直是神经肽对行为调节这一新兴概念的主要组成部分。雌激素在离散脑区对催产素具有深刻调节作用，以及催产素随后在雌激素依赖性反应中的作用，有助于阐明催产素的行为效应。例如，雌性性行为依赖雌激素，雌激素显著增加下丘脑腹内侧核中的催产素结合，在此脑区注入催产素可增加雌性性行为。催产素和雌激素在母性行为调节中的作用也存在类似的相关性。这些行为效应的一个可能潜在原因是，作为一种抗焦虑剂，催产素减少了社交互动中固有的抑制作用。实验室中的行为测试通常包括将动物置于新环境中，如幼崽取回装置或交配场所，并使其接触陌生的同种个体。这些刺激可能会引发应激反应，而催产素或许可以减轻这种焦虑。最近在小鼠中的证据表明，催产素在雌激素处理的雌性小鼠中具有抗焦虑特性（麦卡锡和戈德曼，1994年），并支持这样一种假说，即催产素在大脑中作用的一个统一原则是通过减少相关焦虑来促进社交互动。
