title: Characterization of a novel subtype of hippocampal interneurons that express corticotropin-releasing hormone.
abstract: A subset of corticotropin-releasing hormone (CRH) neurons was previously identified in the hippocampus with unknown function. Here we demonstrate that hippocampal CRH neurons represent a novel subtype of interneurons in the hippocampus, exhibiting unique morphology, electrophysiological properties, molecular markers, and connectivity. This subset of hippocampal CRH neurons in the mouse reside in the CA1 pyramidal cell layer and tract tracing studies using AAV-Flex-ChR2-tdTomato reveal dense back-projections of these neurons onto principal neurons in the CA3 region of the hippocampus. These hippocampal CRH neurons express both GABA and GAD67 and using in vitro optogenetic techniques, we demonstrate that these neurons make functional connections and release GABA onto CA3 principal neurons. The location, morphology, and importantly the functional connectivity of these neurons demonstrate that hippocampal CRH neurons represent a unique subtype of hippocampal interneurons. The connectivity of these neurons has significant implications for hippocampal function.
authors.affiliation: Graduate Program in Neuroscience, Department of Neuroscience, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hooper
authors.affiliation: Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts.
authors.forename: Jamie
authors.initials: J
authors.lastname: Maguire
mesh_terms: D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology*; D007150:Immunohistochemistry; D007395:Interneurons / Q000166:cytology* / Q000502:physiology*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008564:Membrane Potentials; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D056347:Neuroanatomical Tract-Tracing Techniques; D062308:Optogenetics; D018408:Patch-Clamp Techniques; D016133:Polymerase Chain Reaction; D059010:Single-Cell Analysis; D046509:Tissue Culture Techniques; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D008164:Luminescent Proteins; D005680:gamma-Aminobutyric Acid; D003346:Corticotropin-Releasing Hormone; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1
keywords: CRH; GABA; hippocampus; inhibition; interneuron