title: Role of the RVM in Descending Pain Regulation Originating from the Cerebrospinal Fluid-Contacting Nucleus.
abstract: Evidence has suggested that cerebrospinal fluid-contacting nucleus (CSF-contacting nucleus) is correlated with the development and recurrence of pain. A recent research showed that the CSF-contacting nucleus acts as a component of the descending 5-hydroxytryptamine (5-HT) system and plays a role in descending pain inhibition. However, limited studies are conducted to investigate the relationship between the CSF-contacting nucleus and pain. In present study, we explored the effect of CSF-contacting nucleus on nociceptive behaviors in both normal and neuropathic rats via targeted ablation of the CSF-contacting nucleus in the brainstem, using cholera toxin subunit B-saporin (CB-SAP), a cytotoxin coupled to cholera toxin subunit B. The CB-SAP-treated rats showed aggravated thermal hyperalgesia and mechanical allodynia. Also, results from immunohistochemical experiments showed that rostral ventromedial medulla (RVM) received fiber projection from the CSF-contacting nucleus, which disappeared after ablation of the CSF-contacting nucleus, and the CB-SAP treated rats showed downregulation of c-Fos expression in the RVM as compared with the rats receiving i.c.v. injection of phosphate buffer saline (PBS). A significant downregulation of 5-HT-labeled neurons and tryptophan hydroxylase 2 (TPH2) as the marker of 5-HT cells in the RVM, and 5-HT expression in spinal dorsal horn in both normal and chronic constriction injury (CCI) rats after i.c.v. injection of CB-SAP was observed. These results suggested that RVM may be involved in descending pain modulation originating from the CSF-contacting nucleus.
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Fei
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Songsong
authors.initials: S
authors.lastname: Chen
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Qiangqiang
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China.
authors.forename: Lihong
authors.initials: L
authors.lastname: Sun
authors.affiliation: Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, 221004, Jiangsu Province, China. licaizhang001@163.com.
authors.forename: Licai
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D006930:Hyperalgesia / Q000378:metabolism / Q000473:pathology; D008297:Male; D008526:Medulla Oblongata / Q000737:chemistry* / Q000502:physiology*; D010146:Pain / Q000378:metabolism* / Q000473:pathology*; D011712:Pyramidal Tracts / Q000737:chemistry* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: 5-HT; Cerebrospinal fluid-contacting nucleus; Descending pain regulation; RVM