title: Hippocampal Dendritic Spines Are Segregated Depending on Their Actin Polymerization.
abstract: Dendritic spines are mushroom-shaped protrusions of the postsynaptic membrane. Spines receive the majority of glutamatergic synaptic inputs. Their morphology, dynamics, and density have been related to synaptic plasticity and learning. The main determinant of spine shape is filamentous actin. Using FRAP, we have reexamined the actin dynamics of individual spines from pyramidal hippocampal neurons, both in cultures and in hippocampal organotypic slices. Our results indicate that, in cultures, the actin mobile fraction is independently regulated at the individual spine level, and mobile fraction values do not correlate with either age or distance from the soma. The most significant factor regulating actin mobile fraction was the presence of astrocytes in the culture substrate. Spines from neurons growing in the virtual absence of astrocytes have a more stable actin cytoskeleton, while spines from neurons growing in close contact with astrocytes show a more dynamic cytoskeleton. According to their recovery time, spines were distributed into two populations with slower and faster recovery times, while spines from slice cultures were grouped into one population. Finally, employing fast lineal acquisition protocols, we confirmed the existence of loci with high polymerization rates within the spine.
authors.affiliation: Institut de Neurociències, Departament de Bioquímica i Biología Molecular, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193 Barcelona, Spain; VIB Center for Biology of Disease, KU Leuven, 3000 Leuven, Belgium; Center for Human Genetics and Leuven Institute for Neuroscience and Disease, KU Leuven, 3000 Leuven, Belgium.
authors.forename: Nuria
authors.initials: N
authors.lastname: Domínguez-Iturza
authors.affiliation: Advanced Optical Microscopy Unit, Scientific and Technological Centers, Medical School, University of Barcelona, 08036 Barcelona, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Calvo
authors.affiliation: INMED, Unite Mixte de Recherche 901, INSERM, Aix-Marseille Université, 13009 Marseille, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Benoist
authors.affiliation: Molecular Neurobiology Department, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), 28049 Madrid, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Esteban
authors.affiliation: Institut de Neurociències, Departament de Bioquímica i Biología Molecular, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193 Barcelona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Morales
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D049229:Dendritic Spines / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D009924:Organ Culture Techniques; D058105:Polymerization; D051381:Rats
chemical_list: D000199:Actins