Mechanism

Neurotransmitters and Submission

Neurochemistry underlies submissive behaviors in Old World Monkeys. The neurotransmitters dopamine, serotonin and norepinephrine all seem to play a part in submissive behaviors.

In a study done by Kaplan et al. (2002) involving cynomolgus monkeys, serotonin levels remained constant throughout the range of social ranks, indicating that serotonin is not exclusively responsible for submissive behavior. Further analyses show consistent findings with other studies which indicate that higher amounts of serotonin cause female cynomolgus monkeys to display submissive behaviors and take a subordinate role in the social tree.

serotonin, dopamine, and norepinephrine In Kaplan’s study, dopamine showed a positive correlation to aggressive behaviors, but another study done by Grant et al (1998) showed that submissive female monkeys show lower binding potential to some dopamine receptors.

In the study done by Kaplan et al. (2002) wih cynomolgus monkeys, Norepinephrine also showed a positive correlation to aggressive behaviors.

Challenges to Mechanistic Understanding

There are many problems when it comes to understanding the mechanisms of submissive behavior.

  • Given all these data, it seems most likely that there are a range of neurotransmitters which act as mechanisms for submissive behaviors. Part of the problem is trying to generalize across a range of different species.
  • Another issue involves the fact that all in all, scientists do not understand neurotransmitters and their interactions with each other perfectly, so it is entirely possible that there is a single chemical which influences dopamine, serotonin, and norepinephrine levels in primates’ brains.

 

The chemical structures for serotonin (N2OC10H12), dopamine (C8H11NO2), and norepinephrine (C8H11NO3)

agression/submission graph

CSF HVA (a kind of dopamine), 5-HIAA (a kind of serotonin) and MHPH (a kind of norepinephrine) levels calculated by adding the mean concentrations with to the standard error in 11 dominant and 14 submissive male Cynomolgus monkeys. A partial correlation analysis shows a significant association between submission and serotonin levels while the same test eliminates the significance in the calculation of the norepinephrine. (6).