CELLULAR-LOCALIZATION AND EXPRESSION OF THE SEROTONIN TRANSPORTER IN MOUSE-BRAIN

The high-affinity serotonin (5-HT) transporter (5-HTT) plays an import ant role in the removal of extracellular serotonin, thereby modulating and terminating the action of this neurotransmitter at various pre-an d post-synaptic serotonergic receptors and heteroreceptors. In order t o characterize the anatomical distribution of the 5-HTT in mouse brain , in situ hybridization histochemistry using ?S-35-labeled riboprobes was performed. These results were compared with 5-HTT binding site dis tribution as evaluated by [I-125]RTI-55 autoradiography. High levels o f 5-HTT mRNA were detected in all brain stem raphe nuclei, with variat ions in labeling among the various subnuclei. Those bl ain arena known ; to possess serotonergic cell bodies stained intensely for both 5-HTT mRNA and 5-HTT binding sites. In contrast to previous findings in rat brain, the highest densities of 5-HTT sites were found in areas outsi de the raphe complex, particularly in the substantia nigra, globus pal lidus, and superior colliculi. (C) 1997 Elsevier Science B.V.