title: Electron microscopy examination of galanin-like peptide (GALP)-containing neurons in the rat hypothalamus.
abstract: Galanin-like peptide (GALP) is a novel peptide which is isolated from the porcine hypothalamus. GALP-containing neurons are present in the arcuate nucleus (ARC), being particularly densely concentrated in medial posterior regions. To observe the ultrastructure and synaptic relationships of GALP-containing neurons in the ARC, light and immunoelectron microscopy techniques were used. At the light microscope level, GALP-containing neurons were observed distributed rostrocaudally throughout the ARC, with the majority present in the posterior, periventricular zones. At the electron microscope level, many immunopositive dense-cored vesicles were evident in the perikarya, dendrites and axon terminals of the GALP-containing neurons. Furthermore, these neurons received synapses from immunonegative axon terminals that were symmetric in the case of synapses made on perikarya, and both asymmetric and symmetric for synapses made on dendrites. Axon terminals of GALP-containing neurons often made synapses on immunonegative dendrites. Such synapses were all symmetric. Synapses were also found between axon terminals and perikarya as well as dendrites of GALP-containing neurons. These findings suggest that the physiological role of the GALP-containing neurons in the ARC is based on complex synaptic relationships between GALP-containing neurons and either GALP-immunopositive or -immunonegative neurons.
authors.affiliation: Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Jian-Lian
authors.initials: JL
authors.lastname: Guan
authors.forename: Haruaki
authors.initials: H
authors.lastname: Kageyama
authors.forename: Qing-Ping
authors.initials: QP
authors.lastname: Wang
authors.forename: Fumiko
authors.initials: F
authors.lastname: Takenoya
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kita
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ohtaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Shioda
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism* / Q000648:ultrastructure; D001369:Axons / Q000378:metabolism* / Q000648:ultrastructure; D002450:Cell Communication / Q000502:physiology; D003712:Dendrites / Q000378:metabolism* / Q000648:ultrastructure; D044089:Galanin-Like Peptide / Q000096:biosynthesis*; D008297:Male; D046529:Microscopy, Electron, Transmission; D051381:Rats; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D044089:Galanin-Like Peptide