title: RACK1 inhibits morphine re-exposure via inhibition of Src.
abstract: OBJECTIVE
  We previously demonstrated that receptor for activated C kinase 1 (RACK1) inhibited phosphorylated extracellular signal-regulated kinase (p-ERK) during morphine reward in mice. In the present study, we examined the role of Src in regulating the inhibition of p-ERK in the brain following RACK1 over-expression during morphine reward.
  
  
  METHODS
  Mice were subcutaneously injected with morphine on days 2, 4, 6, and 8 after pre-test (day 1), and saline was delivered the following day. After mice showed place preference, RACK1 over-expression plasmid was administered by intraventricular injection 20 minutes after morphine injection on days 11 and 13. Conditioned place preference (CPP) was measured on days 14, 15, 19, and 20.
  
  
  RESULTS
  Chronic morphine injection increased Src and p-ERK expression in cortex and hippocampus, and mice exhibited increased place preference. Intraventricular administration of RACK1 reduced Src and p-ERK levels in cortex and hippocampus, as well as morphine reward. At 7 days of final RACK1 administration, the effects of RACK1 on Src and p-ERK disappeared, and morphine place preference was restored.
  
  
  CONCLUSIONS
  We demonstrated that RACK1 acts on ERK activation via Src in morphine reward in mice.
authors.affiliation: Key Laboratory of Chronobiology, School of Huaxi Preclinical Medicine and Forensic Medicine, Sichuan University, Chengdu, China.
authors.forename: Qiaofeng
authors.initials: Q
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Yanyou
authors.initials: Y
authors.lastname: Liu
authors.forename: Rui
authors.initials: R
authors.lastname: Lu
authors.forename: Quan
authors.initials: Q
authors.lastname: Yuan
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhou
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D003213:Conditioning, Psychological / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009479:Neuropeptides / Q000494:pharmacology*; D010455:Peptides / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*; D000075370:Receptors for Activated C Kinase; D012201:Reward; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection / Q000379:methods; D019061:src-Family Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D009479:Neuropeptides; D010455:Peptides; C090294:RACK1 protein, mouse; D000075370:Receptors for Activated C Kinase; C070301:peptide I; D009020:Morphine; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases