Department of Psychology, University at Buffalo, Buffalo, NY, USA.
Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, USA.
Physiol Behav. 2019 Jul 1;206:125-133. doi: 10.1016/j.physbeh.2019.04.004. Epub 2019 Apr 2.
The neuropeptide, arginine vasopressin (AVP), is thought to contribute to sex differences in normative and pathological social development by regulating social motivation. Recent studies using Brattleboro rats that have a mutation in the Avp gene, however, have suggested that AVP impacts adolescent social behaviors of males and females in a similar manner through actions on behavioral state (i.e., arousal). In the present study, we made use of a recently developed operant conditioning paradigm to test whether the chronic, lifelong AVP deficiency caused by the Brattleboro mutation impacts the reinforcement value of social stimuli during adolescence. Operant responding for access to a familiar conspecific was assessed in male and female adolescent wild type (WT; normal AVP), heterozygous Brattleboro (HET), and homozygous Brattleboro (HOM) rats. Following the social reinforcement test, rats were tested in the same operant paradigm except that the social reinforcer was replaced with a light reinforcer to determine whether effects of the Brattleboro mutation were specific to social stimuli or a general characteristic of operant conditioning. WT males directed a greater proportion of their responding toward the social and light stimuli than WT females; only males exhibited a preference for these reinforcers over unreinforced ports. The sex difference in social reinforcement was absent in HOM rats, whereas the sex difference in light reinforcement was present in all genotypes. These data indicate that adolescent males are more sensitive to the reinforcing properties of social and light stimuli, and that the sex difference in social, but not light, reinforcement depends upon normal levels of AVP. These findings support the hypothesis that AVP plays a critical role in sex differences in social development by acting on factors that influence social motivation.
神经肽精氨酸加压素（AVP）被认为通过调节社会动机对正常和病理性社会发展中的性别差异有贡献。然而，最近使用 Brattleboro 大鼠（该大鼠在 Avp 基因中有突变）的研究表明，AVP 通过对行为状态（即觉醒）的作用，以相似的方式影响雄性和雌性青少年的社会行为。在本研究中，我们利用最近开发的操作性条件反射范式来测试 Brattleboro 突变引起的慢性、终身 AVP 缺乏是否会影响青春期社会刺激的强化价值。在雄性和雌性青春期野生型（WT；正常 AVP）、杂合子 Brattleboro（HET）和纯合子 Brattleboro（HOM）大鼠中评估了获得熟悉同种动物的操作性反应。在社会强化测试之后，在相同的操作性条件反射范式中对大鼠进行了测试，只是用灯光强化物代替了社会强化物，以确定 Brattleboro 突变的影响是否特定于社会刺激或操作性条件反射的一般特征。WT 雄性比 WT 雌性更多地将其反应指向社会和灯光刺激；只有雄性表现出对这些强化物的偏好而不是无强化物的端口。HOM 大鼠中不存在社会强化的性别差异，而所有基因型中都存在灯光强化的性别差异。这些数据表明，青春期雄性对社会和灯光刺激的强化特性更为敏感，而社会强化而不是灯光强化的性别差异取决于正常水平的 AVP。这些发现支持这样一种假设，即 AVP 通过作用于影响社会动机的因素在社会发展中的性别差异中起关键作用。
