title: Chronic benzodiazepine treatment decreases spine density in cortical pyramidal neurons.
abstract: The adult brain retains a substantial capacity for synaptic reorganization, which includes a wide range of modifications from molecular to structural plasticity. Previous reports have demonstrated that the structural remodeling of excitatory neurons seems to occur in parallel to changes in GABAergic neurotransmission. The function of neuronal inhibitory networks can be modified through GABAA receptors, which have a binding site for benzodiazepines (BZ). Although BZs are among the most prescribed drugs, is not known whether they modify the structure and connectivity of pyramidal neurons. In the present study we wish to elucidate the impact of a chronic treatment of 21 days with diazepam (2mg/kg, ip), a BZ that acts as an agonist of GABAA receptors, on the structural plasticity of pyramidal neurons in the prefrontal cortex of adult mice. We have examined the density of dendritic spines and the density of axonal en passant boutons in the cingulate cortex. Although no significant changes were observed in their anxiety levels, animals treated with diazepam showed a decrease in the density of spines in the apical dendrites of pyramidal neurons. Most GFP-expressing en passant boutons in the upper layers of the cingulate cortex had an extracortical origin and no changes in their density were detected after diazepam treatment. These results indicate that the chronic potentiation of GABAergic synapses can induce the structural remodeling of postsynaptic elements in pyramidal neurons.
authors.affiliation: Neurobiology Unit and Program in Basic and Applied Neurosciences, Cell Biology Dpt., Universitat de València, Spain.
authors.forename: Yasmina
authors.initials: Y
authors.lastname: Curto
authors.affiliation: Neurobiology Unit and Program in Basic and Applied Neurosciences, Cell Biology Dpt., Universitat de València, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Garcia-Mompo
authors.affiliation: Neurobiology Unit and Program in Basic and Applied Neurosciences, Cell Biology Dpt., Universitat de València, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Bueno-Fernandez
authors.affiliation: Neurobiology Unit and Program in Basic and Applied Neurosciences, Cell Biology Dpt., Universitat de València, Spain; CIBERSAM: Spanish National Network for Research in Mental Health, Spain; Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Spain. Electronic address: nacher@uv.es.
authors.forename: Juan
authors.initials: J
authors.lastname: Nacher
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D049229:Dendritic Spines / Q000187:drug effects* / Q000648:ultrastructure; D003975:Diazepam / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D058785:GABA-A Receptor Agonists / Q000009:adverse effects*; D008297:Male; D008822:Mice, Transgenic; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000648:ultrastructure; D017966:Pyramidal Cells / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D058785:GABA-A Receptor Agonists; D003975:Diazepam
keywords: Diazepam; En passant boutons; GABAA receptor agonist; Neuronal structural plasticity