The Roles of Dopamine D1 Receptor on the Social Hierarchy of Rodents and Non-human Primates

Abstract

Background:Although dopamine has been suggested to play a role in mediating social behaviors of individual animals, it is not clear whether such dopamine signaling contributes to attributes of social groups such as social hierarchy.Methods:In this study, the effects of the pharmacological manipulation of dopamine D1 receptor function on the social hierarchy and behavior of group-housed mice and macaques were investigated using a battery of behavioral tests.Results:D1 receptor blockade facilitated social dominance in mice at the middle, but not high or low, social rank in the groups without altering social preference among mates. In contrast, the administration of a D1 receptor antagonist in a macaque did not affect social dominance of the drug-treated animal; however, relative social dominance relationships between the drug-treated and nontreated subjects were altered indirectly through alterations of social affiliative relationships within the social group.Conclusions:These results suggest that dopamine D1 receptor signaling may be involved in social hierarchy and social relationships within a group, which may differ between rodents and primates.

The Effects of Housing Density on Social Interactions and Their Correlations with Serotonin in Rodents and Primates

“…Presence or absence of social affiliations and aggressions in every 10 seconds (1,800 frames for 30 minutes) were measured, and a number of frames in which the events were present was expressed as percentage of time out of a whole recording period that these events occupied. Social affiliations and aggressions were defined as we have previously described 56 . Inter-rater reliabilities for the rates of aggressions and social affiliations between the experimenters at off-line analysis were very high (Cohen’s kappa = 0.93, with confidence interval at 0.90–0.96), indicating reliable behavioral assessments 57 .…”

The Roles of Serotonin in Decision-making under Social Group Conditions

“…Four out of 8 groups tested in Ph.1 were further subjected to a tube rank test, which is another behavioral test to examine social rank of mice, and examined its correlation between FAP. In the tube rank test, David’s score (DS), which is an index of social dominance, was calculated based on a dyadic proportion of wins and losses, as conducted in our previous studies 27 , 28 . A significant positive correlation was observed between FAP and DS (r = 0.853, p < 0.001; Fig.…”

“…In social groups of non-human primates such as macaques, as well as other wild animals, linear social hierarchy exists, and a correlation between social ranks and FAP has been reported 15 , 30 . In contrast, although presence of a linear social hierarchy in rodent social groups has been observed 27 , 28 , 31 , whether mice living in social groups also exhibit FAP had yet to be determined. In this study, we found that, similar to non-human primates, FAP correlated with social ranks is also present in mouse social groups.…”

“…Thus, it is highly unlikely that 5-HT is the only neurotransmitter involved in decision-making under conflict in social group environments. We have previously shown that DA, through activation of D1 and D2 receptors, plays an important role in the construction of social hierarchy in both rodents and primates 27 , 28 , such that DA is also likely to affect decision-making under conflict associated with social group setting, although DA may mediate different aspects of the decision-making process than 5-HT. It is also important to examine whether activation of fear conditioning-associated limbic regions such as the amygdala 44 can be observed in test subjects under the social conformity test, since, if freezing of test subjects is due to emotional contagion, such limbic areas may be activated, whereas if freezing is caused by social pressure, other brain areas may be primarily activated.…”

Dopamine-dependent social information processing in non-human primates

“…The equivalent volume of saline (SAL) was given as a control treatment. The doses of drugs were determined based on our previous macaque studies (Yamaguchi et al 2017a , b , c ), in which we tested the D1 and D2 antagonists for the visual attention task to social vs. non-social images as well as freely moving macaques in social groups. In particular, the doses of SCH23390 and sulpiride used in this study was not only previously found effective to alter various behavior of the drug-administered macaques and visual attention to social vs. non-social images, but particularly importantly, macaques were still able to sustain gazing to the images for a fixed duration during NIRS recordings.…”