title: Neurochemical properties of BDNF-containing neurons projecting to rostral ventromedial medulla in the ventrolateral periaqueductal gray.
abstract: The periaqueductal gray (PAG) modulates nociception via a descending pathway that relays in the rostral ventromedial medulla (RVM) and terminates in the spinal cord. Previous behavioral pharmacology and electrophysiological evidence suggests that brain-derived neurotrophic factor (BDNF) plays an important role in descending pain modulation, likely through the PAG-RVM pathway. However, detailed information is still lacking on the distribution of BDNF, activation of BDNF-containing neurons projecting to RVM in the condition of pain, and neurochemical properties of these neurons within the PAG. Through fluorescent in situ hybridization (FISH) and immunofluorescent staining, the homogenous distributions of BDNF mRNA and protein were observed in the four subregions of PAG. Both neurons and astrocytes expressed BDNF, but not microglia. By combining retrograde tracing methods and formalin pain model, there were more BDNF-containing neurons projecting to RVM being activated in the ventrolateral subregion of PAG (vlPAG) than other subregions of PAG. The neurochemical properties of BDNF-containing projection neurons in the vlPAG were investigated. BDNF-containing projection neurons expressed the autoreceptor TrkB in addition to serotonin (5-HT), neurotensin (NT), substance P (SP), calcitonin gene related peptide (CGRP), nitric oxide synthase (NOS), and parvalbumin (PV) but not tyrosine decarboxylase (TH). It is speculated that BDNF released from projection neurons in the vlPAG might participate in the descending pain modulation through enhancing the presynaptic release of other neuroactive substances (NSs) in the RVM.
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Jun-Bin
authors.initials: JB
authors.lastname: Yin
authors.affiliation: Department of Anesthesiology, Fuzhou General Hospital Affiliated to Fujian Medical University Fuzhou, China.
authors.forename: Huang-Hui
authors.initials: HH
authors.lastname: Wu
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Dong
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Wei
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Ya-Cheng
authors.initials: YC
authors.lastname: Lu
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Sheng-Xi
authors.initials: SX
authors.lastname: Wu
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University Xi'an, China.
authors.forename: Yun-Qing
authors.initials: YQ
authors.lastname: Li
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D004195:Disease Models, Animal; D005557:Formaldehyde; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology* / Q000503:physiopathology; D017628:Microglia / Q000378:metabolism; D009434:Neural Pathways / Q000502:physiology / Q000503:physiopathology; D009474:Neurons / Q000502:physiology*; D009496:Neurotensin / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010146:Pain / Q000503:physiopathology*; D010320:Parvalbumins / Q000378:metabolism; D010487:Periaqueductal Gray / Q000502:physiology* / Q000503:physiopathology; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D020813:Receptor, trkB / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D013373:Substance P / Q000378:metabolism; D014445:Tyrosine Decarboxylase / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D010320:Parvalbumins; D012333:RNA, Messenger; D005557:Formaldehyde; D012701:Serotonin; D013373:Substance P; D009496:Neurotensin; D019001:Nitric Oxide Synthase; D020813:Receptor, trkB; D014445:Tyrosine Decarboxylase; D015740:Calcitonin Gene-Related Peptide
keywords: brain-derived neurotrophic factor (BDNF); neurochemical properties; periaqueductal gray (PAG); projection neurons; rostral ventromedial medulla (RVM)