Brainstem levels of transcription factor AP-2 in rat are changed after treatment with phenelzine, but not with citalopram.
BACKGROUND
Before therapeutic effect is obtained after treatment with antidepressant drugs, like serotonin selective reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAO-Is) there is an initial lag-period of a few weeks. Neuronal adaptations on a molecular level are supposed to be involved in the initiation of the antidepressant effect. Transcription factor AP-2 is essential for neuronal development and many genes involved in the brainstem monoaminergic systems have binding sites for AP-2 in their regulatory regions. The genotype of the AP-2beta isoform has been associated with e.g. anxiety-related personality traits and with platelet MAO activity. In addition, previous studies have shown that the levels of AP-2alpha and AP-2beta in rat whole brain were decreased after 10 days of treatment with citalopram (SSRI) and imipramine (TCA), and were increased with phenelzine (MAO-I).


RESULTS
In the present study, we report that treatment with citalopram for 1, 7 or 21 days did not have effect on the AP-2 levels in rat brainstem. However, after treatment with phenelzine for 1, 7 or 21 days the levels of AP-2alpha and AP-2beta had increased after 7 days, but had returned to control levels at day 21.


CONCLUSIONS
The decrease in AP-2 levels in rat whole brain previously seen after treatment with citalopram does not seem to be localised to the brainstem, it may rather occur in the monoaminergic terminal projection areas. The present data suggest that the increase in AP-2 levels previously seen in rat whole brain after subchronic treatment with phenelzine is located in the brainstem. It cannot, however, be excluded that other brain regions are involved.
Berggard
Cecilia
C
Department of Neuroscience, Unit of Pharmacology, Uppsala University, PO Box 593 BMC, SE-751 24, Uppsala, Sweden. cecilia.berggard@neuro.uu.se
Damberg
Mattias
M
Oreland
Lars
L
D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001933:Brain Stem / Q000187:drug effects* / Q000378:metabolism; D015283:Citalopram / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D010624:Phenelzine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D050656:Transcription Factor AP-2 / Q000235:genetics / Q000378:metabolism*
D000928:Antidepressive Agents; D050656:Transcription Factor AP-2; D015283:Citalopram; D010624:Phenelzine