Expression of the Serotonin Transporter in the Ventrolateral Part of the Solitary Tract Nucleus in Rats during the Early Postnatal Period in Normal Conditions and in Serotoninergic System Deficiency during the Prenatal Period of Development

Abstract

An immunocytochemical study method was used to investigate the expression of the serotonin transporter (5-HTT) in the ventrolateral part of the solitary tract nucleus in Wistar rats during the early postnatal period (days 5 and 10) in normal conditions (n = 10) and in conditions of prenatal serotonin deficiency (n = 12). During the early postnatal period, the ventrolateral section of the solitary tract nucleus was found to show transient expression of 5-HTT, most marked in the caudal part of the ventral subnucleus. The numbers of neurons synthesizing 5-HTT in the rostral part of the ventral and lateral subnuclei were small and did not change with age. The caudal part of the ventral subnucleus contained a large number of neurons synthesizing 5-HTT on day 5 of the postnatal period, and this number decreased significantly with age. The caudal part of the lateral subnucleus contained a small number of cells expressing 5-HTT, and this number also decreased with age. 5-HTT expression levels were significantly higher in the caudal areas of both the ventral and lateral subnuclei than in the rostral areas. Prenatal serotonin deficiency decreased the numbers of neurons synthesizing 5-HTT in the nuclei studied here.