Functional correlates for 5-HT1A receptors in maternally deprived rats displaying anxiety and depression-like behaviors

Maternal separation is known to induce long-term changes in neuroendocrine and emotional responsiveness to stress in a large variety of models. We examined an animal model of early deprivation in Sprague–Dawley rats consisting of separating litters from their mothers and littermates 3 h daily during postnatal days 2 to 15. In adulthood, maternally deprived rats in comparison with non-deprived controls exhibited an increase in anxiety and depression-related behaviors in the open-field and forced swim tests. Because serotonin (5-HT) 5-HT_1A receptors seem to play an important role in the pathophysiology of major depression and in the mechanism of action of antidepressants, we investigated if 5-HT_1A receptor function is altered in deprived rats. Although the hypothermic response to the 5-HT_1A receptor agonist 8-OH-DPAT was increased in adult deprived rats compared to non-deprived control group, no differences between groups were found in the effect of the systemic 8-OH-DPAT administration on serotoninergic cell firing in dorsal raphe nucleus and in the 5-HT release at the ventral hippocampus levels. These results suggest that 5-HT_1A receptors are not substantially affected in adult Sprague–Dawley rats that were subjected to a maternal deprivation 3 h daily during the neonatal period.