EXPRESSION OF SEROTONIN TRANSPORTER MESSENGER-RNA IN HUMAN BRAIN-STEMRAPHE NUCLEI

The distribution of the messenger RNA (mRNA) encoding the serotonin tr ansporter was investigated in the entire extent of the ascending raphe systems of the human brainstem, using a sensitive cRNA probe. This mR NA is abundant in the neurons of the raphe nuclei, especially in the d orsal and median raphe. The subregional distribution of this mRNA clos ely corresponds to that described for tryptophan hydroxylase in immuno cytochemical studies. It is expressed at the highest levels in ventral and ventrolateral subregions of the dorsal raphe, with lower levels o f expression in the median raphe, oral pontine reticular nuclei, and t he supralemniscal cell groups. These results provide a description of the distribution of this mRNA in normal subjects and will serve as the basis for future studies of the subregional distribution of this mRNA in the brains of depressed patients and those who have committed suic ide. (C) 1996 American College of Neuropsychopharmacology