title: Electrical synapses connect a network of gonadotropin releasing hormone neurons in a cichlid fish.
abstract: Initiating and regulating vertebrate reproduction requires pulsatile release of gonadotropin-releasing hormone (GnRH1) from the hypothalamus. Coordinated GnRH1 release, not simply elevated absolute levels, effects the release of pituitary gonadotropins that drive steroid production in the gonads. However, the mechanisms underlying synchronization of GnRH1 neurons are unknown. Control of synchronicity by gap junctions between GnRH1 neurons has been proposed but not previously found. We recorded simultaneously from pairs of transgenically labeled GnRH1 neurons in adult male Astatotilapia burtoni cichlid fish. We report that GnRH1 neurons are strongly and uniformly interconnected by electrical synapses that can drive spiking in connected cells and can be reversibly blocked by meclofenamic acid. Our results suggest that electrical synapses could promote coordinated spike firing in a cellular assemblage of GnRH1 neurons to produce the pulsatile output necessary for activation of the pituitary and reproduction.
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305; and.
authors.forename: Yunyong
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305.
authors.forename: Scott A
authors.identifier: http://orcid.org/0000-0001-7634-1395
authors.initials: SA
authors.lastname: Juntti
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305.
authors.forename: Caroline K
authors.initials: CK
authors.lastname: Hu
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305; and.
authors.forename: John R
authors.initials: JR
authors.lastname: Huguenard
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305 rfernald@stanford.edu.
authors.forename: Russell D
authors.initials: RD
authors.lastname: Fernald
mesh_terms: D000818:Animals; D023681:Cichlids / Q000502:physiology*; D017630:Connexins / Q000378:metabolism; D054351:Electrical Synapses; D005260:Female; D017629:Gap Junctions; D053263:Gene Regulatory Networks; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D008297:Male; D008469:Meclofenamic Acid / Q000737:chemistry; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D010902:Pituitary Gland / Q000378:metabolism; D009435:Synaptic Transmission; D019076:Transgenes
chemical_list: D017630:Connexins; D049452:Green Fluorescent Proteins; D007987:Gonadotropin-Releasing Hormone; D008469:Meclofenamic Acid
keywords: GnRH; cichlid; electrophysiology; gap junction; transgenic