The NMB human neuronal cell line, transfected with a newly prepared plasmid expressing rat serotonin transporter (NMB-rSERT), shows specific [3H]5-HT uptake which is blocked by citalopram and fenfluramine (F) stereoisomers with IC50 values (I nM, 0.5 μM (dF) and 5 μm (IF), respectively) which are similar to those found in rat brain synaptosomes. d- Fenfluramine (0.5 and 10 μM) also stimulates tritium release from NMB-rSERT cells preloaded with [3H-]-5-HT. The d-fenfluramine-induced [3H-15-HT release is blocked by 0.3 μM citalopram and is dependent on the density of SERT expressed per cell, but is not affected by removal of Ca++ ions from the incubation medium. Manipulation of the Na+ gradient across the plasma membrane (replacing 60 mM NaCl with an equimolar concentration of KCl or choline) also induced [3H-]5-HT release from NMB-rSERT cells, which was inhibited by 0.3 μM citalopram. These results, together with the finding that NMB rSERT cells preloaded with 500 nM unlabelled 5-HT take up [3H-]d- fenfluramine, make NMB-rSERT cells a valuable tool for studying the transporter-mediated exchange release induced by amphetamine derivatives.
- Serotonin release
- Serotonin transporter
- Transfected human neuroblastoma cells
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience
- Drug Discovery