title: Role of dopamine D3 receptors in basal nociception regulation and in morphine-induced tolerance and withdrawal.
abstract: Repeated administration of opioids such as morphine leads to the development of tolerance to their pain-relieving effects as well as to physical dependence. Although the association between the dopamine system and the molecular mechanisms of morphine-induced antinociceptive tolerance has been studied, the possible interaction between morphine-induced tolerance and D3 receptors has not been investigated. In the present study, male mice lacking the dopamine D3 receptor gene were used to investigate the function of D3 receptors in the development of morphine-induced tolerance and withdrawal. Compared with wild-type (WT) mice, the dopamine D3 receptor knockout (D3R KO) mice showed pronounced hypoalgesia. The D3R KO mice clearly developed lower morphine-induced tolerance and showed attenuated withdrawal signs compared with the WT mice. These results suggest that D3 receptors regulate basal nociception and are involved in the development of morphine-induced tolerance and withdrawal.
authors.affiliation: Forensic Department, Xi'an Jiaotong University School of Medicine, 76# West Yanta Road, Xi'an 710061, PR China. Litao050428@mail.xjtu.edu.cn
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Hou
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Yan
authors.forename: Teng
authors.initials: T
authors.lastname: Chen
authors.forename: Sheng-Bing
authors.initials: SB
authors.lastname: Li
mesh_terms: D000818:Animals; D004361:Drug Tolerance / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009020:Morphine / Q000008:administration & dosage*; D059225:Nociception / Q000502:physiology*; D010147:Pain Measurement / Q000379:methods; D050637:Receptors, Dopamine D3 / Q000172:deficiency / Q000502:physiology*; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology* / Q000523:psychology
chemical_list: D050637:Receptors, Dopamine D3; D009020:Morphine