title: Involvement of monoaminergic systems in the antidepressant-like effect of Eugenia brasiliensis Lam. (Myrtaceae) in the tail suspension test in mice.
abstract: BACKGROUND
  Several species of Eugenia L. are used in folk medicine for the treatment of various diseases. Eugenia brasiliensis is used for the treatment of inflammatory diseases, whereas Eugenia. uniflora is used for the treatment of symptoms related to depression and mood disorders, and is used in Brazil by the Guarani Indians as a tonic stimulant.
  
  
  OBJECTIVE
  To investigate the antidepressant-like effect of hydroalcoholic extracts of different plant species of genus Eugenia and to characterize the participation of the monoaminergic systems in the mechanism of action of the specie that afforded the most prominent antidepressant-like efficacy.
  
  
  METHODS
  In the first set of experiments, the effects of hydroalcoholic extracts of Eugenia beaurepaireana, Eugenia brasiliensis, Eugenia catharinae, Eugenia umbelliflora and Eugenia uniflora and the antidepressant fluoxetine (positive control) administered acutely by p.o. route were evaluated in the tail suspension test (TST) and locomotor activity was assessed in the open-field test in mice. In the second set of experiments, the involvement of the monoaminergic systems in the antidepressant-like activity of Eugenia brasiliensis was evaluated by treating mice with several pharmacological agonists and antagonists. The effects of the combined administration of sub-effective doses of Eugenia brasiliensis and the antidepressants fluoxetine, imipramine and bupropion were also evaluated.
  
  
  RESULTS
  The administration of the extracts from Eugenia brasiliensis, Eugenia catharinae and Eugenia umbelliflora, but not Eugenia beaurepaireana and Eugenia uniflora, exerted a significant antidepressant-like effect, without altering locomotor activity. The behavioral profile was similar to fluoxetine. Pre-treatment of mice with ketanserin, haloperidol, SCH23390, sulpiride, prazosin and yohimbine prevented the reduction of immobility time induced by Eugenia brasiliensis. Treatment with sub-effective doses of WAY100635, SKF38393, apomorphine, phenylephrine, but not clonidine, combined with a sub-effective dose of Eugenia brasiliensis decreased the immobility time in the TST. Furthermore, the combined administration of sub-effectives doses of Eugenia brasiliensis with fluoxetine, imipramine and bupropion produced an antidepressant-like effect.
  
  
  CONCLUSIONS
  This study show, for the first time, the antidepressant-like effect of species of the genus Eugenia, especially Eugenia brasiliensis, whose effects in the TST seem to be mediated by serotoninergic (5-HT(1A) and 5-HT(2) receptors), noradrenergic (α(1)-adrenoceptor) and dopaminergic (dopamine D(1) and D(2) receptors) systems.
authors.affiliation: Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis-SC, Brazil.
authors.forename: André R S
authors.initials: AR
authors.lastname: Colla
authors.forename: Daniele G
authors.initials: DG
authors.lastname: Machado
authors.forename: Luis E B
authors.initials: LE
authors.lastname: Bettio
authors.forename: Guilherme
authors.initials: G
authors.lastname: Colla
authors.forename: Michele D A
authors.initials: MD
authors.lastname: Magina
authors.forename: Inês M C
authors.initials: IM
authors.lastname: Brighente
authors.forename: Ana Lúcia S
authors.initials: AL
authors.lastname: Rodrigues
mesh_terms: D018674:Adrenergic Antagonists / Q000494:pharmacology; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001522:Behavior, Animal / Q000187:drug effects; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D019417:Hindlimb Suspension / Q000502:physiology; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D017982:Receptors, Biogenic Amine / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D027842:Syzygium
chemical_list: D018674:Adrenergic Antagonists; D000928:Antidepressive Agents; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D010936:Plant Extracts; D017982:Receptors, Biogenic Amine; D012702:Serotonin Antagonists