[EXPRESSION OF SEROTONIN TRANSPORT PROTEIN IN THE DORSAL RAPHE NUCLEUS IN THE EARLY POSTNATAL PERIOD IN RATS]

In this work an expression of serotonin transport protein (5-HTT) was studied in the dorsal raphe nucleus (DRN)--in its dorsal, ventral and lateral subnuclei in Wistar rats (n = 15) during the early postnatal period. Histological methods and immunocytochemical staining demonstrating 5-HTT were used in the investigation. It was shown that at postnatal Day 5 major part of neurons of the subnuclei studied intensively expressed 5-HTT. However, by Day 10, the level of its expression decreased dramatically, but with age (by Day 20) the expression was increased once again. This was manifested by the augmentation of size of 5-HTT-positive neuronal population, the increase in the density of plexus network of their processes. The detected changes of 5-HTT expression indicate the varying degrees of functional activity of serotonin in the DRN in the early postnatal period.