| The alterations induced by social isolation are characteristic of the depressive state in non-human primates. However, cortisol released during stressful events can be ameliorated by oxytocin (OT) release. In order to demonstrate depression-like symptoms we utilize a separation social support test to determine responses to stress at 6 months of age using the Callithrix jacchus (n=26, f=13, m=13). The test began when the animals were placed in a small urine chamber in a room isolated from the marmoset colony. Behavior was recorded in 4x 20-minute blocks and urine collected non-invasively following each 20-minutes. The behaviors: lick, phee call, scent mark, and smell were examined singly and combined to provide a coping rating. Degree of activity was also used as a measure of positive coping. Cortisol and oxytocin were analyzed by Enzyme Immunoassay. We grouped the subjects by basal cortisol levels (>40 v <40 µg/mg creatinine). We found that animals with <40 basal cortisol levels showed higher activity than those with >40 (p= 0.044) prior to isolation. However, coping scores compared to cortisol differences were not significantly different (p>0.999). As we expected, an OT increase accompanied the cortisol increase (p=0.025) with isolation. Hence, social disruption induces stress responses and behavioral coping strategies. These data are important for understanding behavior before comparing with the feasibility of scent-based separation social reward testing. Supported by NIHRO1HD086057. |
