Reserpine or chronic paroxetine treatments do not modify the vesicular monoamine transporter 2 expression in serotonin-containing regions of the rat brain.
To date, very little information is available about the regulation of vesicular monoamine transporter in central serotonergic regions. The expression of the vesicular monoamine transporter 2 (VMAT2) has been studied in the serotonergic system of the rat brain after an 18 day treatment with the serotonin selective-reuptake inhibitor paroxetine (10 mg/kg, i.p., once daily). This treatment, while increasing serotonergic transmission, did not modify either VMAT2 mRNA expression or (3)H-dihydrotetrabenazine binding site density in any of the studied regions. These results suggest that VMAT2 regulation in the central serotonergic system is not involved in the mechanism of action of antidepressants. In addition, a single administration of reserpine (5 mg/kg, s.c.), while blocking the vesicular monoamine uptake function, had no effect on VMAT2 immunoreactivity in the dorsal raphe nucleus 2 or 30 days after injection. It is concluded that neither a reduction (reserpine) nor an enhancement (paroxetine) of the serotonin transmission induces VMAT2 regulation in serotonergic system in the rat brain.
Vilpoux
C
C
Unité de Neuropsychopharmacologie Expérimentale, UPRES-A CNRS 6036, IFRMP No. 23, Site universitaire du Madrillet, Avenue de l'Université, 76800, Saint Etienne du Rouvray, France.
Leroux-Nicollet
I
I
Naudon
L
L
Raisman-Vozari
R
R
Costentin
J
J
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001692:Biological Transport; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D015283:Citalopram / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D066298:In Vitro Techniques; D008024:Ligands; D008297:Male; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009479:Neuropeptides; D009638:Norepinephrine / Q000378:metabolism; D017374:Paroxetine / Q000008:administration & dosage / Q000494:pharmacology*; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012110:Reserpine / Q000494:pharmacology*; D012701:Serotonin / Q000378:metabolism*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D013747:Tetrabenazine / Q000031:analogs & derivatives / Q000378:metabolism; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
D015283:Citalopram; D004298:Dopamine; D008024:Ligands; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009479:Neuropeptides; D009638:Norepinephrine; D017374:Paroxetine; D012110:Reserpine; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors; D013747:Tetrabenazine; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; C493454:Slc18a2 protein, rat; C032811:dihydrotetrabenazine