title: Ability of baclofen to prevent somatic manifestations and neurochemical changes during nicotine withdrawal.
abstract: BACKGROUND
  Nicotine (NIC), the major active component of tobacco, is critical in the maintenance of the smoking habit. The aims of the present study were to analyze the behavioural and neurochemical variations during NIC withdrawal syndrome in mice, and whether they are prevented with baclofen (BAC, GABA(B) receptor agonist).
  
  
  METHODS
  Swiss-Webster albino mice received NIC (2.5 mg/kg, s.c.) 4 times daily, for 7 consecutive days. On day 8 (the day of the experiment), NIC-treated mice received the nicotine antagonist mecamylamine (MEC, 2 mg/kg, i.p.) 1h after the last dose of NIC. A second group of dependent mice received BAC (2mg/kg, i.p.) before MEC-precipitated abstinence. The somatic signs were measured for 30 min. Dopamine (DA), serotonin (5-hydroxytryptamine; 5-HT) and its metabolites concentrations were determined by HPLC in the striatum, cortex and hippocampus.
  
  
  RESULTS
  The global score was greater in the abstinent group compared to the control group. Moreover, the global score time course showed a higher increase at 10 min compared to the global score at 5 min or 30 min after MEC-precipitated NIC withdrawal. In addition, the global score was attenuated by BAC. The DA and dihydroxyphenyl acetic acid (DOPAC) cortical levels decreased in the abstinent group, while BAC reestablished these levels 10 min after NIC withdrawal. Furthermore, DA and 5-HT striatal levels decreased during NIC withdrawal, and BAC reverted this decrease.
  
  
  CONCLUSIONS
  In conclusion, the prevention of NIC withdrawal signs by BAC could be related to changes in dopaminergic and serotonergic activity.
authors: Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Piso, Buenos Aires C1113AAD, Argentina.
authors: Andrés P
authors: AP
authors: Varani
authors: Lirane Machado
authors: LM
authors: Moutinho
authors: Mariela
authors: M
authors: Calvo
authors: Graciela N
authors: GN
authors: Balerio
mesh_terms: D000818:Animals; D001418:Baclofen / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D001522:Behavior, Animal / Q000187:drug effects; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D008297:Male; D008464:Mecamylamine / Q000009:adverse effects* / Q000097:blood; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D009538:Nicotine / Q000009:adverse effects* / Q000097:blood; D018722:Nicotinic Agonists / Q000009:adverse effects* / Q000097:blood; D018733:Nicotinic Antagonists / Q000009:adverse effects* / Q000097:blood; D016540:Smoking Cessation / Q000379:methods; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy* / Q000378:metabolism / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D008464:Mecamylamine; D009538:Nicotine; D001418:Baclofen