RESUMO
The present study investigated the effect of early maternal separation on anxiety and hypophyso-adrenal system activity to anterodorsal thalamic nuclei (ADTN) lesion in male rats as adults in order to compare this with previous results with female rats. During the first 3 weeks of life, male rats were isolated 4.5 hr daily and tested as adults. Thirty days after ADTN lesion we found that adrenocorticotropic hormone (ACTH) plasma levels were affected neither by maternal separation nor by ADTN lesion. Plasma corticosterone (CORT) concentration was increased with lesion of the ADTN in maternally separated rats. A significant increase in plasma catecholamine concentration was induced by early maternal separation. In ADTN-lesioned rats, plasma norepinephrine (NE) concentration was significantly lower than in the respective sham-lesioned groups. In terms of anxiety, there were no significant effects of early experience. However, the ADTN lesion tended to decrease anxiety-related behavior.
