Presence and characterization of the serotonin transporter in human resting lymphocytes.
Although evidence exists of the presence of a serotonin (5-HT) reuptake system in lymphocytes, no information is available on the pharmacological characterization of this structure. Our study aimed to investigate this matter, therefore, by means of the binding of [3H]-paroxetine ([3H]PAR), a selective 5-HT reuptake inhibitor (SSRI), which is considered the ligand of choice for binding studies. Lymphocytes were obtained from a pool of 20 healthy subjects who volunteered for the study. The results showed the presence of a specific and saturable [3H]PAR binding to lymphocyte membranes, with a Hill number close to unity indicative of the presence of one site only. The most potent drugs inhibiting [3H]PAR binding were SSRIs (paroxetine, fluoxetine, citalopram) followed by clomipramine, imipramine, and 5-HT, whereas haloperidol, mazindol, and nomifensine had a negligible effect. These findings suggest that [3H]-PAR in human resting lymphocytes specifically labels the 5-HT transporter.
Marazziti
D
D
Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, University of Pisa, Italy.
Rossi
A
A
Giannaccini
G
G
Baroni
S
S
Lucacchini
A
A
Cassano
G B
GB
D000293:Adolescent; D000328:Adult; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017374:Paroxetine / Q000378:metabolism*; D012016:Reference Values; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors / Q000378:metabolism*; D014316:Tritium
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017374:Paroxetine; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors; D014316:Tritium; C493230:SLC6A4 protein, human