title: Synaptic connections of the neurokinin 1 receptor-like immunoreactive neurons in the rat medullary dorsal horn.
abstract: The synaptic connections between neurokinin 1 (NK1) receptor-like immunoreactive (LI) neurons and γ-aminobutyric acid (GABA)-, glycine (Gly)-, serotonin (5-HT)- or dopamine-β-hydroxylase (DBH, a specific marker for norepinephrinergic neuronal structures)-LI axon terminals in the rat medullary dorsal horn (MDH) were examined under electron microscope by using a pre-embedding immunohistochemical double-staining technique. NK1 receptor-LI neurons were observed principally in laminae I and III, only a few of them were found in lamina II of the MDH. GABA-, Gly-, 5-HT-, or DBH-LI axon terminals were densely encountered in laminae I and II, and sparsely in lamina III of the MDH. Some of these GABA-, Gly-, 5-HT-, or DBH-LI axon terminals were observed to make principally symmetric synapses with NK1 receptor-LI neuronal cell bodies and dendritic processes in laminae I, II and III of the MDH. The present results suggest that neurons expressing NK1 receptor within the MDH might be modulated by GABAergic and glycinergic inhibitory intrinsic neurons located in the MDH and 5-HT- or norepinephrine (NE)-containing descending fibers originated from structures in the brainstem.
authors.affiliation: Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Qi
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.forename: Le
authors.initials: L
authors.lastname: Yang
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Sheng-Xi
authors.initials: SX
authors.lastname: Wu
authors.forename: Yun-Qing
authors.initials: YQ
authors.lastname: Li
mesh_terms: D000818:Animals; D005455:Fluorescent Antibody Technique; D005998:Glycine / Q000378:metabolism; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D009474:Neurons / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D009638:Norepinephrine / Q000378:metabolism; D020671:Posterior Horn Cells / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D013569:Synapses / Q000378:metabolism / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D018040:Receptors, Neurokinin-1; D012701:Serotonin; D005680:gamma-Aminobutyric Acid; D005998:Glycine; D009638:Norepinephrine