2026 ECNP Congress

PS02-2030

The influence of oxytocin on psycho-emotional behavior and social interaction in early postnatal immobilized male rats

Lamara Machavariani — M. Butskhrikidze, M. Svanidze, M. Siradze, N. Bukia · LEPL Iv.Beritashvili Center of Experimental Biomedicine, Neuroendocrinology, Tbilisi, Georgia

2026 ECNP Congress

Introduction

The early postnatal period represents a “critical window” for neurodevelopment, where the brain’s plasticity makes it highly susceptible to environmental stressors. Physical and psychological trauma during this phase can permanently recalibrate the body’s homeostatic mechanisms. According to the Centers for Disease Control and Prevention (CDC), nearly 8% of children and adolescents suffer from neurobiological disorders often rooted in early-life stress. Such stressors disrupt the delicate balance of the oxytocinergic system and alter glucocorticoid receptor expression, leading to long-term emotional dysregulation [1, 2]. Specifically, early stress is known to diminish empathy and prosocial behaviors in adulthood [3]. Understanding how these neural circuits can be repaired via hormonal intervention is essential for developing therapeutic strategies for social and emotional deficits.

Methods

Experiments were conducted on two groups of male rats: Control (Group I) and Immobilized (Group II). The immobilized group was subjected to chronic stress from PN0 to PN20 (2 hours daily). Following this period, oxytocin was administered intranasally to a subgroup for 10 days to evaluate its corrective potential. At adulthood (PN90), behavioral phenotypes were assessed using the Social Preference Test (a three-chamber apparatus and the Open Field test (anxiety and locomotion). The study monitored the time spent with social partners (“stranger” and “familiar” rats) versus inanimate objects over 600-second intervals. Statistical significance was determined using ANOVA and Post hoc Tukey tests (n=10 per group).

Results

.The Control Group exhibited robust social motivation. In the Social Preference Test, rats spent significantly more time interacting with the confined “stranger” rat than in the empty chamber (F2,6= 11.31, P≤0.05). When presented with a choice between a “familiar” rat and a novel object, they showed a clear preference for the social subject (F2,6=102.11 P≤0.05), indicating healthy empathy levels.

Conversely, Stressed Rats showed marked behavioral impairment. The Open Field test revealed decreased locomotion (crossed squares, F1,8= 8.12 P≤0.05),), fewer center entries, and reduced head-flicks (P≤0.01). Simultaneously, grooming frequency and duration—markers of heightened anxiety—increased significantly (P≤0.01). In social tests, these rats failed to show preference, spending equal time in social and non-social zones, reflecting a loss of social motivation and empathy.

Intranasal Oxytocin Administration effectively reversed these deficits. Oxytocin-treated stressed rats demonstrated a significant increase in social engagement with the familiar rat (P≤0.01) and a reduction in anxiety-like behaviors in the Open Field ( P≤0.05) . Interestingly, oxytocin did not significantly alter the behavior of the control group, suggesting its effects are specifically therapeutic for stress-induced imbalances. The data suggest that early postnatal stress triggers a down-regulation of oxytocin receptors (OXTR) in the hypothalamus and prefrontal cortex, while simultaneously causing HPA axis dysregulation through elevated CRH and cortisol-like levels. This biochemical shift inhibits the neural pathways required for empathy. Intranasal oxytocin appears to bypass these barriers, restoring social interest and emotional stability.

Conclusions

Oxytocin is a potent modulator of social behavior and offers a promising path for treating stress-induced neurobiological disorders.

The research was supported by Shota Rustaveli National Science Foundation FR-24-401

References

  1. Young, L.J., Donaldson, Z.R., 2015. Oxytocin, vasopressin, and the neurogenetics of sociality. Science 347 (6224), aaa6760.
  2. Gunnar, M.R., Quevedo, K., 2007. The neurobiology of stress and development. Annu. Rev. Psychol. 58, 145–173.
  3. Rilling, J.K., Young, L.J., 2014. The biology of mammalian parenting and its effect on offspring social development. Science 345 (6198), 771–776.