Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas, USA.
Program in Neuroscience, School of Pharmacy, University of Kansas, Lawrence, Kansas, USA.
Genes Brain Behav. 2023 Dec;22(6):e12861. doi: 10.1111/gbb.12861. Epub 2023 Jul 30.
Death of a loved one is recognized as one of life's greatest stresses, and 10%-20% of bereaved individuals will experience a complicated or prolonged grieving period that is characterized by intense yearning for the deceased. The monogamous prairie vole (Microtus ochrogaster) is a rodent species that forms pair bonds between breeding partners and has been used to study the neurobiology of social behaviors and isolation. Male prairie voles do not display distress after isolation from a familiar, same-sex conspecific; however, separation from a bonded female partner increases emotional, stress-related, and proximity-seeking behaviors. Here, we tested the investigatory response of male voles to partner odor during a period of social loss. We found that males who lost their partner spent significantly more time investigating partner odor but not non-partner social odor or food odor. Bachelor males and males in intact pairings did not respond uniquely to any odor. Furthermore, we examined dopamine (DA) receptor mRNA expression in the anterior insula cortex (aIC), nucleus accumbens (NAc), and anterior cingulate (ACC), regions with higher activation in grieving humans. While we found some effects of relationship type on DRD1 and DRD2 expression in some of these regions, loss of a high-quality opposite-sex relationship had a significant effect on DA receptor expression, with pair-bonded/loss males having higher expression in the aIC and ACC compared with pair-bonded/intact and nonbonded/loss males. Together, these data suggest that both relationship type and relationship quality affect reunion-seeking behavior and motivational neurocircuits following social loss of a bonded partner.
亲人的离世被认为是人生最大的压力之一，10%-20%的丧亲者会经历一个复杂或延长的悲伤期，其特征是对死者的强烈渴望。一夫一妻制的草原田鼠（Microtus ochrogaster）是一种啮齿动物，它在繁殖伴侣之间形成伴侣关系，并被用于研究社会行为和隔离的神经生物学。雄性草原田鼠在与熟悉的同性同种个体隔离后不会表现出痛苦；然而，与绑定的雌性伴侣分离会增加情绪、与压力相关的行为和接近行为。在这里，我们测试了雄性田鼠在社交丧失期间对伴侣气味的探究反应。我们发现，失去伴侣的雄性田鼠花在调查伴侣气味上的时间显著增加，但不会增加对非伴侣社交气味或食物气味的反应。单身雄性和处于完整配对中的雄性对任何气味都没有独特的反应。此外，我们检查了前脑岛皮层（aIC）、伏隔核（NAc）和前扣带皮层（ACC）中的多巴胺（DA）受体 mRNA 表达，这些区域在悲伤的人类中激活程度更高。虽然我们发现一些区域的 DRD1 和 DRD2 表达受到关系类型的影响，但高质量异性关系的丧失对 DA 受体表达有显著影响，与完整配对/丧失的雄性相比，配对/完整和非配对/丧失的雄性在前脑岛皮层和前扣带皮层中的表达更高。总之，这些数据表明，关系类型和关系质量都会影响社交伴侣丧失后寻求团聚的行为和动机神经回路。
