title: Inhibitory effects of processed Aconiti tuber on morphine-induced conditioned place preference in rats.
abstract: OBJECTIVE
  Our previous studies indicated that processed Aconiti tuber (PAT), a traditional Chinese herbal medicine, had antinociceptive effects and inhibitory effects on morphine tolerance by activation of kappa-opioid receptor (KOR). Preclinical studies also demonstrated that KOR agonists functionally attenuate addictive behaviors of morphine, such as conditioned place preference (CPP). Therefore, we hypothesize that PAT may inhibit morphine-induced CPP in rats.
  
  
  METHODS
  (1) Five groups of rats (n=8 for each group) were alternately subcutaneous (s.c.) injected with morphine 10mg/kg (one group receive normal saline as a control) and normal saline for 8 days and oral co-administrated with distilled water or PAT 0.3, 1.0, or 3.0 g/kg daily on days 2-9 during CPP training, respectively. (2) Other four groups of rats were randomly s.c. injected with nor-binaltorphimine (nor-BNI; 5mg/kg) or normal saline (as a control) 120 min before alternately s.c. with morphine and normal saline and oral co-administrated with distilled water or PAT 3.0 g/kg daily. Each rat was acquired pre-conditioning and post-conditioning CPP data and assayed dynorphin concentrations by radioimmunoassay in rat's nucleus accumbens (NAc) after CPP training.
  
  
  RESULTS
  (1) PAT 1.0 or 3.0 g/kg dose-dependently decreased the morphine-induced increase of CPP scores. (2) Nor-BNI completely antagonized the inhibition of PAT on morphine-induced CPP. (3) PAT dose-dependently increased dynorphin content in rats' NAc after CPP training.
  
  
  CONCLUSIONS
  (1) PAT dose-dependently inhibited morphine-induced CPP. (2) The inhibition of PAT on morphine-induced CPP was probably due to activation of KOR by increasing dynorphin release in rats' NAc.
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2nd Road, Guangzhou, Guangdong 510080, China.
authors.forename: Guiyun
authors.initials: G
authors.lastname: Wu
authors.forename: Wenqi
authors.initials: W
authors.lastname: Huang
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Qiaobo
authors.initials: Q
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.forename: Haihua
authors.initials: H
authors.lastname: Shu
mesh_terms: D031841:Aconitum; D000818:Animals; D016739:Behavior, Addictive / Q000188:drug therapy* / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D004399:Dynorphins / Q000378:metabolism; D008297:Male; D009021:Morphine Dependence / Q000188:drug therapy*; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D008517:Phytotherapy; D035281:Plant Tubers; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000819:agonists
chemical_list: D004365:Drugs, Chinese Herbal; D009292:Narcotic Antagonists; D017473:Receptors, Opioid, kappa; C051844:norbinaltorphimine; D009271:Naltrexone; D004399:Dynorphins