title: Function of dendritic spines on hippocampal inhibitory neurons.
abstract: The majority of γ-aminobutyric acid (GABA)ergic interneurons have smooth dendrites with no or only few dendritic spines, but certain types of spiny GABAergic interneurons do actually contain substantial numbers of spines. The explanation for such spines has so far been purely structural: They increase the dendritic surface area and thus provide the opportunity to accommodate larger numbers of synapses. We reasoned that there may be specific functional properties for these spines and therefore, undertook to characterize interneuron spines functionally. We find a remarkable similarity to pyramidal cell spines: They receive excitatory synapses with calcium impermeable α-amino-3-hydroxy-5-methyl-4 isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors, compartmentalize biochemical signals, and display activity-dependent morphological plasticity. Nevertheless, notable differences in spine density, neck length, and spine-dendrite coupling exist. Thus, dendritic spines on inhibitory interneurons have a number of important functional properties that go substantially beyond simply expanding the dendritic surface area. It therefore seems likely that spiny and aspiny interneurons may have very different roles in neural circuit function and plasticity.
authors.affiliation: Max Planck Institute of Neurobiology, Department "Synapses - Circuits - Plasticity", Martinsried 82152, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Scheuss
authors.affiliation: Max Planck Institute of Neurobiology, Department "Synapses - Circuits - Plasticity", Martinsried 82152, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Bonhoeffer
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000367:Age Factors; D000818:Animals; D049229:Dendritic Spines / Q000502:physiology*; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D007395:Interneurons / Q000502:physiology / Q000648:ultrastructure*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects; D009479:Neuropeptides / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology / Q000648:ultrastructure; D017470:Receptors, Glutamate / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology
chemical_list: D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D017470:Receptors, Glutamate; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2
keywords: GABAergic inhibitory interneuron; GAD65 mouse line; dendritic spine; spine–dendrite coupling; structural plasticity