PRESENCE OF SEROTONIN(1A) (5-HT1A) RECEPTOR MESSENGER-RNA WITHOUT BINDING OF [H-3] 8-OH-DPAT IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS

The authors investigated the presence of serotonin receptor type 1A (5 -HT1A) as labeled by the specific ligand H-3-8 hydroxy-2-(di-N-propyla mino)tetralin (H-3-8-OH-DPAT) in saturation experiments, and the expre ssion of the mRNA encoding them, in human peripheral blood mononuclear cells (PBMC). In situ hybridization experiments were performed as wel l. The results, showing that the binding of [H-3]-8-OH-DPAT to lymphoc yte membranes increased linearly up to 100 nM without reaching saturat ion, may indicate that the H-3-8-OH-DPAT was not specifically labeling the 5-HT1A receptor. By contrast, the expression studies revealed 5-H T1A mRNA in PBMC. These findings suggest that, despite the presence of mRNA, 5-HT1A receptors are not expressed in PBMC, at least in healthy controls.