EFFECTS OF THE ALTERED SEROTONERGIC SIGNALING BY NEONATAL TREATMENT WITH 5,7-DIHYDROXYTRYPTAMINE, RITANSERIN OR CLOMIPRAMINE ON THE ADRENOCORTICAL STRESS-RESPONSE AND THE GLUCOCORTICOID RECEPTOR-BINDING IN THEHIPPOCAMPUS IN ADULT-RATS

The aim of the present study is to investigate the effect of neonatal alterations in 5-HT signalling on the regulation of endocrine stress r esponse in adult rats. The neonatal blockade of 5-HT transmission by 5 ,7-DHT or ritanserin treatment did not alter the density of glucocorti coid receptor (GR) binding sites in the hippocampus, although a 5,7-DH T-induced lesion was clearly shown to decrease in 5-HT content by grea ter than 80% in the hippocampus. In addition, the animals pretreated w ith the blockade of 5-HT transmission during early life did not exhibi t a hyperresponsiveness of the adrenocortical response to stress. On t he other hand, the neonatal administration of the 5-HT uptake inhibito r, clomipramine, was shown to lower the stress responsiveness of the a drenocortical axis in adulthood.