title: Synaptic interactions between ghrelin- and neuropeptide Y-containing neurons in the rat arcuate nucleus.
abstract: Morphological relationships between neuropeptide Y- (NPY) like and ghrelin-like immunoreactive neurons in the arcuate nucleus (ARC) were examined using light and electron microscopy techniques. At the light microscope level, both neuron types were found distributed in the ARC and could be observed making contact with each other. Using a preembedding double immunostaining technique, some NPY-immunoreactive axon terminals were observed at the electron microscope level to make synapses on ghrelin-immunoreactive cell bodies and dendrites. While the axo-somatic synapses were mostly symmetric in nature, the axo-dendritic synapses were both symmetric and asymmetric. In contrast, ghrelin-like immunoreactive (ghrelin-LI) axon terminals were found to make synapses on NPY-like immunoreactive (NPY-LI) dendrites although no NPY-like immunoreactive perikarya were identified receiving synapses from ghrelin-LI axon terminals. NPY-like axon terminals were also found making synapses on NPY-like neurons. Axo-axonic synapses were also identified between NPY- and ghrelin-like axon terminals. The present study shows that NPY- and ghrelin-LI neurons could influence each other by synaptic transmission through axo-somatic, axo-dendritic and even axo-axonic synapses, and suggests that they participate in a common effort to regulate the food-intake behavior through complex synaptic relationships.
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: Qing-Ping
authors.initials: QP
authors.lastname: Wang
authors.forename: Haruaki
authors.initials: H
authors.lastname: Kageyama
authors.forename: Fumiko
authors.initials: F
authors.lastname: Takenoya
authors.forename: Tohru
authors.initials: T
authors.lastname: Kita
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Funahashi
authors.forename: Seiji
authors.initials: S
authors.lastname: Shioda
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism* / Q000648:ultrastructure; D054439:Ghrelin; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D009478:Neuropeptide Y / Q000378:metabolism*; D036361:Peptide Hormones / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D054439:Ghrelin; D009478:Neuropeptide Y; D036361:Peptide Hormones