title: Antidepressant fluoxetine suppresses neuronal growth from both vertebrate and invertebrate neurons and perturbs synapse formation between Lymnaea neurons.
abstract: Current treatment regimes for a variety of mental disorders involve various selective serotonin reuptake inhibitors such as Fluoxetine (Prozac). Although these drugs may 'manage' the patient better, there has not been a significant change in the treatment paradigm over the years and neither have the outcomes improved. There is also considerable debate as to the effectiveness of various selective serotonin reuptake inhibitors and their potential side-effects on neuronal architecture and function. In this study, using mammalian cortical neurons, a dorsal root ganglia cell line (F11 cells) and identified Lymnaea stagnalis neurons, we provide the first direct and unequivocal evidence that clinically relevant concentrations of Fluoxetine induce growth cone collapse and neurite retraction of both serotonergic and non-serotonergic neurons alike in a dose-dependent manner. Using intracellular recordings and calcium imaging techniques, we further demonstrate that the mechanism underlying Fluoxetine-induced effects on neurite retraction from Lymnaea neurons may involve lowering of intracellular calcium and a subsequent retardation of growth cone cytoskeleton. Using soma-soma synapses between identified presynaptic and postsynaptic Lymnaea neurons, we provide further direct evidence that clinically used concentrations of Fluoxetine also block synaptic transmission and synapse formation between cholinergic neurons. Our study raises alarms over potentially devastating side-effects of this antidepressant drug on neurite outgrowth and synapse formation in a developing/regenerating brain. Our data also demonstrate that drugs such as Fluoxetine may not just affect communication between serotonergic neurons but that the detrimental effects are widespread and involve neurons of various phenotypes from both vertebrate and invertebrate species.
authors.affiliation: Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Alberta T2N 4N1, Canada.
authors.forename: Fenglian
authors.initials: F
authors.lastname: Xu
authors.forename: Collin
authors.initials: C
authors.lastname: Luk
authors.forename: Maria P
authors.initials: MP
authors.lastname: Richard
authors.forename: Wali
authors.initials: W
authors.lastname: Zaidi
authors.forename: Svetlana
authors.initials: S
authors.lastname: Farkas
authors.forename: Angela
authors.initials: A
authors.lastname: Getz
authors.forename: Arthur
authors.initials: A
authors.lastname: Lee
authors.forename: Jan
authors.initials: J
authors.lastname: van Minnen
authors.forename: Naweed I
authors.initials: NI
authors.lastname: Syed
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005473:Fluoxetine / Q000494:pharmacology*; D020439:Growth Cones / Q000187:drug effects*; D008195:Lymnaea / Q000166:cytology*; D018613:Microscopy, Confocal; D009433:Neural Inhibition / Q000187:drug effects; D016501:Neurites / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D000199:Actins; D018687:Antidepressive Agents, Second-Generation; D017077:Culture Media, Conditioned; D005473:Fluoxetine; D002118:Calcium