Two major distinct subpopulations of neurokinin-3 receptor-expressing neurons in the superficial dorsal horn of the rat spinal cord.
This study was designed to provide evidence for elucidating the mechanisms of neurokinin-3 receptor (NK3) in spinal pain modulation. First, colocalization of NK3 with the micro -opioid receptor (MOR1) was studied in the spinal dorsal horn of the rat. Confocal microscopy showed that about 44% of NK3-expressing neurons in laminae I and II were immunoreactive for MOR1, which corresponded to about 93% of the total population of MOR1-containing neurons in these laminae. Second, the relationship between NK3/MOR1-coexpressing neurons and those that express nitric oxide synthase (NOS) was examined by using a triple immunofluorescent staining method. About 37% of NK3-immunoreactive neurons were also NOS-immunoreactive, which constituted about 82% of NOS-immunoreacitve neurons in the superficial laminae. However, no triple-labelled neurons were detected. The present results indicate that there are two major distinct subpopulations of NK3-expressing neurons in the superficial dorsal horn, which suggests that the involvement of NK3 receptor in spinal nociception could be mediated by two distinct mechanisms, i.e. opioid and nitric oxide.
Ding
Yu-Qiang
YQ
Institute of Neurosciences, Fourth Military Medical University, Xi'an 710032, People's Republic of China. dingyq@morpheus.wustl.edu
Lu
Chun-Rong
CR
Wang
Hong
H
Su
Chang-Jun
CJ
Chen
Liang-Wei
LW
Zhang
Yuan-Qiang
YQ
Ju
Gong
G
D000344:Afferent Pathways / Q000166:cytology / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D007150:Immunohistochemistry; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D018847:Opioid Peptides / Q000378:metabolism*; D010146:Pain / Q000378:metabolism* / Q000503:physiopathology; D020671:Posterior Horn Cells / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018042:Receptors, Neurokinin-3 / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D018847:Opioid Peptides; D018042:Receptors, Neurokinin-3; D017450:Receptors, Opioid, mu; D009569:Nitric Oxide; D013373:Substance P; D005680:gamma-Aminobutyric Acid; D019001:Nitric Oxide Synthase