Like mothers, fathers play a vital role in the development of the brain and behavior of offspring in mammals with biparental care. Unlike mothers, fathers do not experience the physiological processes of pregnancy, parturition, or lactation before their first contact with offspring. Whether pup exposure can induce the onset of paternal behavior and the underlying neural mechanisms remains unclear. By using Slc:ICR male mice exhibiting maternal-like parental care, the present study found that repeated exposure to pups for six days significantly increased the total duration of paternal behavior and shortened the latency to retrieve and care for pups. Repeated pup exposure increased c-Fos-positive neurons and the levels of dopamine- and TH-positive neurons in the nucleus accumbens (NAc). In addition, inhibition of dopamine projections from the ventral tegmental area to the NAc using chemogenetic methods reduced paternal care induced by repeated pup exposure. In conclusion, paternal behavior in virgin male ICR mice can be initiated by repeated pup exposure via sensitization, and the dopamine system may be involved in this process.

与母亲一样，父亲在双亲照顾的哺乳动物的大脑发育和后代行为中发挥着至关重要的作用。与母亲不同，父亲在第一次接触后代之前不会经历怀孕、分娩或哺乳的生理过程。幼犬暴露是否可以诱导父系行为的发生以及潜在的神经机制仍不清楚。通过使用 Slc:ICR 雄性小鼠表现出母性般的父母照顾，本研究发现，反复接触幼崽六天显着增加了父亲行为的总持续时间，并缩短了检索和照顾幼崽的潜伏期。反复暴露幼犬会增加伏隔核 (NAc) 中 c-Fos 阳性神经元和多巴胺和 TH 阳性神经元的水平。此外，使用化学遗传学方法抑制从腹侧被盖区域到 NAc 的多巴胺投射减少了由反复幼犬暴露引起的父亲照顾。总之，处女雄性 ICR 小鼠的父系行为可以通过致敏反复暴露幼犬来启动，并且多巴胺系统可能参与了这一过程。