DISSERTATION RESEARCH: Effects of placentophagia on anxiety and paternal behavior in male California mice (Peromyscus californicus)

父亲的照顾在哺乳动物中是罕见的，但可能对后代的生存和发育产生关键影响，包括人类。虽然神经内分泌和经验的影响，父亲的行为已经在许多物种的研究，近调控的父照顾的开始仍然知之甚少。在雌性哺乳动物中，与母性开始相关的激素变化（即，怀孕、分娩和哺乳期）通过减少新妈妈对新生儿的焦虑或恐惧反应来激活母性行为。目前尚不清楚焦虑减少是否在男性父母照顾的发病中起着类似的作用，但焦虑的几个生理和行为指标与父亲照顾方面呈负相关。本研究的目的是研究减少焦虑的作用“允许”男性的父性行为的表达。 这项研究与人类和人类行为有很大的相关性，父亲的参与和照顾不足与家庭互动中观察到的许多困难以及儿童作为父母的后续行为有关。 为了验证这一点，研究人员将研究加州的老鼠，它们表现出许多与人类相同的社会行为和家庭结构。 临产的雌性哺乳动物摄入胎盘是非常常见的，并且可以引起母亲的行为和生理变化，从而增强其对后代的照顾。在一些双亲哺乳动物中，父亲也会在幼崽出生时摄取胎盘;然而，雄性吞胎盘的功能尚不清楚。co-PI和PI最近进行的研究发现，当性经验不足的雄性加州小鼠（Peromyscus californicus）通过口服管饲法给予胎盘时，它们随后表现出接近新物体或无关幼崽的延迟减少，以及终纹背床核（与焦虑相关的脑区）中的神经活动（Fos免疫反应性）减少。因此，这些行为和神经的结果表明，胎盘摄入可能会减少男性的焦虑。几项研究发现了间接证据，证明焦虑和父亲的照顾之间存在反比关系，在这个物种和其他物种中。这项研究将验证一个假设，即雄性加州小鼠的胎盘吞噬减少了它们的焦虑，并通过这种方式增加了它们对父亲的反应。第一次怀孕的父亲和处女男性将通过口服管饲法用油中的胎盘或仅油处理，或不处理，随后测试焦虑样行为和父亲行为。将测定血浆中的别孕烯醇酮（一种在胎盘中产生的抗焦虑类固醇），并测定已知调节焦虑和父亲护理的大脑区域中的神经活性（Fos-免疫反应性），以确定胎盘吞噬是否可以通过别孕烯醇酮的抗焦虑作用减少新父亲的焦虑。结果将提供新的见解胎盘功能的意义，男性以及可能的影响，男性父母的照顾。

Paternal care is rare in mammals, but can have a critical influence on offspring survival and development in the species in which it occurs, including humans. Although neuroendocrine and experiential influences on paternal behavior have been studied in numerous species, the proximate regulation of the onset of paternal care remains poorly understood. In female mammals, hormonal changes associated with the onset of motherhood (i.e., with pregnancy, parturition and lactation) activate maternal behavior in part by decreasing new mothers' anxiety-like or neophobic responses towards their newborns. It is unknown whether anxiety reduction plays a similar role in the onset of male parental care, but several physiological and behavioral measures of anxiety have been negatively correlated with aspects of paternal care. The aim of this research is to study the role of reduction in anxiety "permitting" the expression of paternal behavior by males. This research has great relevance to human and human behavior and inadequate paternal involvement and care is associated with many difficulties observed in family interactions and subsequent behavior of children as parents. To test this researcher will study the California mice, which displays many of the same social behavior and family structures as humans. Ingestion of placenta by parturient female mammals is very common, and can elicit behavioral and physiological changes in mothers that enhance their care of offspring. In several biparental mammals, fathers also ingest placenta during the birth of their young; however, the function of placentophagia by males is unknown. Recent research conducted by the co-PI and PI has found that when sexually inexperienced male California mice (Peromyscus californicus) are administered placenta via oral gavage, they subsequently show reduced latencies to approach a novel object or an unrelated pup, as well as reduced neural activity (Fos-immunoreactivity) in the dorsal bed nucleus of the stria terminalis, a brain region associated with anxiety. Thus, these behavioral and neural results suggest that placenta ingestion may reduce anxiety in males. Several studies have found indirect evidence for an inverse relationship between anxiety and paternal care in this and other species. The proposed work will test the hypothesis that placentophagia by male California mice reduces their anxiety, and by doing so may increase their paternal responsiveness. First-time expectant fathers and virgin males will be treated via oral gavage with placenta in oil or oil alone, or left untreated, and subsequently tested for anxiety-like behavior and paternal behavior. Plasma will be assayed for allopregnanolone (an anxiolytic steroid produced in placenta), and neural activity (Fos-immunoreactivity) will be determined in brain areas known to regulate anxiety and paternal care, to determine if placentophagia may reduce anxiety in new fathers through anxiolytic effects of alloprenanolone. Results will provide novel insights into the functional significance of placentophagia by males as well as possible influences on the activation of male parental care.