Neuronal cell lines transfected with the dopamine D2 receptor gene promoter as a model for studying the effects of antidepressant drugs.

The present study investigated the effect of three antidepressant drugs (ADs), desipramine (DMI, a noradrenaline reuptake inhibitor), citalopram (CIT, a selective serotonin reuptake inhibitor) and mianserin (MIA, thought to act as an antagonist of pre-synaptic alpha2 adrenoceptor) on the transcriptional activity of the dopamine D2 receptor gene promoter. The fragment of dopamine D2 receptor gene promoter (-850 to +133) was subcloned into pGL3 vector (Promega), which has an insert coding for luciferase used as a reporter gene. Such construct (pGL3-D2R) was used to transiently transfect the neuroblastoma cell lines, Neuro 2a, SH-SY5Y and NB41A3, which endogenously express the dopamine D2 receptor protein. The obtained results indicate that transcriptional activity of dopamine D2 receptor gene promoter was dose-dependently increased by retinoic acid, forskolin, rolipram and phorbol 12 myristate 13-acetate, as well as by DMI, CIT and MIA. In the Neuro 2a cells, the most significant increase was observed after the ADs were present in the incubation medium at a doses of 0.1-1 microM for 72 h. In the SH-SY5Y cells, the significant increase in the transcriptional activity of D2 receptor gene promoter was observed already after 24-h exposure to DMI. Incubation of the Neuro 2a cells in the presence of forskolin (1 microM) or rolipram (50 microM) (but not phorbol 12-myristate 13-acetate at 0.1 microM) in combination with DMI resulted in the further increase in transcriptional activity of the studied promoter, indicating the involvement of protein kinase A pathway in these effects.