Graduate Program in Neuroscience, University of California, Riverside, CA 92521, USA; Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA.
Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael St., Atlanta, GA 30322, USA.
Horm Behav. 2022 Jan;137:105086. doi: 10.1016/j.yhbeh.2021.105086. Epub 2021 Nov 19.
In biparental species, in which both parents care for their offspring, the neural and endocrine mediators of paternal behavior appear to overlap substantially with those underlying maternal behavior. Little is known, however, about the roles of classical neurotransmitters, such as norepinephrine (NE), in paternal care and whether they resemble those in maternal care. We tested the hypothesis that NE facilitates the initiation of nurturant behavior toward pups in virgin male and female California mice (Peromyscus californicus), a biparental rodent. Virtually all parents in this species are attracted to familiar and unfamiliar pups, while virgins either attack, avoid, or nurture pups, suggesting that the neurochemical control of pup-related behavior changes as mice transition into parenthood. We injected virgin males and females with nepicastat, a selective dopamine β-hydroxylase inhibitor that blocks NE synthesis (75 mg/kg, i.p.), or vehicle 2 h before exposing them to a novel pup, estrous female (males only), or pup-sized novel object for 60 min. Nepicastat significantly reduced the number of males and females that approached the pup and that displayed parental behavior. In contrast, nepicastat did not alter virgins' interactions with an estrous female or a novel object, suggesting that nepicastat-induced inhibition of interactions with pups was not mediated by changes in generalized neophobia, arousal, or activity. Nepicastat also significantly reduced NE levels in the amygdala and prefrontal cortex and increased the ratio of dopamine to NE in the hypothalamus. Our results suggest that NE may facilitate the initiation of parental behavior in male and female California mice.
在双亲物种中，父母双方都照顾自己的后代，雄性亲代行为的神经和内分泌介质似乎与雌性亲代行为的神经和内分泌介质有很大的重叠。然而，关于经典神经递质（如去甲肾上腺素（NE））在亲代照料中的作用，以及它们是否与亲代照料中的作用相似，我们知之甚少。我们检验了以下假设：NE 促进了加利福尼亚鼠（Peromyscus californicus）中雄性和雌性处女的育雏行为的开始，加利福尼亚鼠是一种双亲种啮齿动物。在这个物种中，几乎所有的父母都被熟悉和不熟悉的幼崽所吸引，而处女要么攻击、回避或养育幼崽，这表明随着老鼠过渡到父母身份，与幼崽相关的行为的神经化学控制发生了变化。我们在将处女雄性和雌性暴露于新幼崽、发情雌性（仅雄性）或幼崽大小的新物体 60 分钟之前 2 小时，给处女雄性和雌性注射了 nepicastat，一种选择性多巴胺-β-羟化酶抑制剂，可阻止 NE 合成（75mg/kg，ip）或载体。nepicastat 显著减少了接近幼崽并表现出亲代行为的雄性和雌性的数量。相比之下，nepicastat 并没有改变处女与发情雌性或新物体的相互作用，这表明 nepicastat 诱导的与幼崽相互作用的抑制不是通过改变一般的恐惧症、唤醒或活动来介导的。nepicastat 还显著降低了杏仁核和前额叶皮层中的 NE 水平，并增加了下丘脑多巴胺与 NE 的比值。我们的结果表明，NE 可能促进了加利福尼亚鼠中雄性和雌性亲代行为的开始。
