Expression of serotonin transporter in the dorsal raphe nucleus during the early postnatal period in the normal state and under prenatal deficiency of the serotonergic system in rats

Abstract

The expression of the serotonin transport membrane protein (5-NTT) in the dorsal raphe nucleus (DNR) was investigated in laboratory Wistar rats during the early postnatal period. The results of the immunocytochemical study using primary antibodies--anti-Serotonin transporter antibody (AbCam, UK)--showed that during the first 3 postnatal weeks the intensity of 5-NTT expression in DNR of control animals changes. At the earliest postnatal times the main part of subnuclear neurons (dorsal, ventral and lateral ones) of the dorsal raphe nucleus (DNR-d, DNR-v, DNR-lat) was shown to intensely express 5-NTT. Sites of 5-NTT localization are found on the membrane surface of neuron bodies and processes in neuropile. The reduction in the number of neurons expressing 5-NTT and of its binding sites was observed on P10. At this time a redistribution of 5-NTT localization sites occurs: they are very few on neuron bodies and dendrites but are located rather densely on the plasma membrane of axons. The number of neurons expressing 5-NTT gradually increases with age and in neuropile the density of 5-NTT localization sites rises. It is shown that during the prenatal development the reduction of serotonin level in all parts of the DNR leads to a reduction in both the number of neurons expressing 5-NTT and sites of its localization in the early postnatal period, this trend continuing with age.