title: Neuronal activity regulates diffusion across the neck of dendritic spines.
abstract: In mammalian excitatory neurons, dendritic spines are separated from dendrites by thin necks. Diffusion across the neck limits the chemical and electrical isolation of each spine. We found that spine/dendrite diffusional coupling is heterogeneous and uncovered a class of diffusionally isolated spines. The barrier to diffusion posed by the neck and the number of diffusionally isolated spines is bidirectionally regulated by neuronal activity. Furthermore, coincident synaptic activation and postsynaptic action potentials rapidly restrict diffusion across the neck. The regulation of diffusional coupling provides a possible mechanism for determining the amplitude of postsynaptic potentials and the accumulation of plasticity-inducing molecules within the spine head.
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Bloodgood
authors.forename: Bernardo L
authors.initials: BL
authors.lastname: Sabatini
mesh_terms: D000200:Action Potentials; D000818:Animals; D003593:Cytoplasm / Q000502:physiology; D003712:Dendrites / Q000502:physiology*; D049229:Dendritic Spines / Q000502:physiology*; D004058:Diffusion; D019706:Excitatory Postsynaptic Potentials; D005453:Fluorescence; D058787:GABA-A Receptor Antagonists; D018698:Glutamic Acid / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006624:Hippocampus / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism; D011963:Receptors, GABA-A / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission; D014162:Transfection; D014783:Viscosity
chemical_list: D058787:GABA-A Receptor Antagonists; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; D016194:Receptors, N-Methyl-D-Aspartate; D049452:Green Fluorescent Proteins; D018698:Glutamic Acid