Selective Serotonin Reuptake Inhibitors Potentiate the Rapid Antidepressant-Like Effects of Serotonin4 Receptor Agonists in the Rat |
| |
Authors: | Guillaume Lucas Jenny Du Thomas Romeas Ouissame Mnie-Filali Nasser Haddjeri Graciela Pi?eyro Guy Debonnel |
| |
Institution: | 1. Department of Psychiatry, Centre de Recherche Fernand Seguin, Université de Montréal, Montréal, Québec, Canada.; 2. EAC CNRS 3006, ISPB Université de Lyon 1, Faculty of Pharmacy, Lyon, France.; 3. Department of Psychiatry, Bâtiment de Recherche et de Formation, Université McGill, Montréal, Québec, Canada.;Tokyo Medical and Dental University, Japan |
| |
Abstract: | BackgroundWe have recently reported that serotonin4 (5-HT4) receptor agonists have a promising potential as fast-acting antidepressants. Here, we assess the extent to which this property may be optimized by the concomitant use of conventional antidepressants.Methodology/Principal FindingsWe found that, in acute conditions, the 5-HT4 agonist prucalopride was able to counteract the inhibitory effect of the selective serotonin reuptake inhibitors (SSRI) fluvoxamine and citalopram on 5-HT neuron impulse flow, in Dorsal Raphé Nucleus (DRN) cells selected for their high (>1.8 Hz) basal discharge. The co-administration of both prucalopride and RS 67333 with citalopram for 3 days elicited an enhancement of DRN 5-HT neuron average firing rate, very similar to what was observed with either 5-HT4 agonist alone. At the postsynaptic level, this translated into the manifestation of a tonus on hippocampal postsynaptic 5-HT1A receptors, that was two to three times stronger when the 5-HT4 agonist was combined with citalopram. Similarly, co-administration of citalopram synergistically potentiated the enhancing effect of RS 67333 on CREB protein phosphorylation within the hippocampus. Finally, in the Forced Swimming Test, the combination of RS 67333 with various SSRIs (fluvoxamine, citalopram and fluoxetine) was more effective to reduce time of immobility than the separate administration of each compound.Conclusions/SignificanceThese findings strongly suggest that the adjunction of an SSRI to a 5-HT4 agonist may help to optimize the fast-acting antidepressant efficacy of the latter. |
| |
Keywords: | |
|
|