Vasopressin modulates male squirrel monkeys' behavior during social separation

Area of Science:

• Neuroendocrinology
• Behavioral Neuroscience
• Primate Social Behavior

Background:

• Central arginine-vasopressin (AVP) influences various behaviors in rodents, including social recognition, aggression, and feeding.
• Brain AVP concentrations are linked to gonadal steroid hormone levels.
• Social dominance in male squirrel monkeys correlates with distinct social behaviors and testosterone levels.

Purpose of the Study:

• To investigate the behavioral effects of centrally administered AVP in pair-housed male squirrel monkeys during social separations.
• To determine if social status and associated testosterone levels modulate AVP's behavioral effects.

Main Methods:

• Central administration of AVP and oxytocin (OT) to pair-housed male squirrel monkeys.
• Observation of social behaviors, including scent-marking, grooming, vigilance-checking, and 'isolation-peep' calls, during brief social separations.
• Measurement of plasma testosterone levels to assess social dominance relationships.

Main Results:

• Central AVP administration increased scent-marking and grooming behaviors during social separation.
• These AVP-induced behavioral changes were independent of the monkey's social status and testosterone levels.
• Oxytocin (OT) did not mimic the effects of AVP on scent-marking and grooming.
• Both AVP and OT decreased vigilance-checking and 'isolation-peep' calls.

Conclusions:

• AVP appears to facilitate the stress response in male squirrel monkeys during social separation.
• The observed behavioral effects of AVP are not influenced by testosterone levels associated with social dominance.
• These findings contribute to understanding the neurobiological underpinnings of social behavior and stress responses in primates.