title: Dendritic action potential initiation in hypothalamic gonadotropin-releasing hormone neurons.
abstract: It is dogma that action potentials are initiated at the soma/axon hillock of neurons. However, dendrites often exhibit conductances necessary for spike generation and represent functionally independent processing compartments within neurons. GnRH neurons provide an interesting neuronal phenotype with simple, relatively unbranched, unipolar or bipolar dendrites of extensive lengths (>1000 microm) covered in spines. These neurons control fertility and must integrate a variety of internal homeostatic and external environmental cues. We used imaging, electrophysiological, and modeling studies to understand how they integrate and process information along dendrites. Simultaneous recordings from distal dendrites and somata of individual GnRH neurons indicate distal dendrites are the primary site of spike initiation in these cells. Compartmental modeling indicates that sites of spike initiation depend upon location of excitatory input and dendrite geometry. Together, these studies demonstrate a novel pattern of spike generation in mammalian neurons and indicate that afferent inputs within distal dendritic microdomains directly initiate action potentials.
authors.affiliation: Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA.
authors.forename: Carson B
authors.initials: CB
authors.lastname: Roberts
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Campbell
authors.forename: Allan E
authors.initials: AE
authors.lastname: Herbison
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Suter
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D003712:Dendrites / Q000378:metabolism / Q000502:physiology*; D004594:Electrophysiology; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D015222:Sodium Channels / Q000378:metabolism / Q000502:physiology
chemical_list: D015222:Sodium Channels; D007987:Gonadotropin-Releasing Hormone