title: Evidence for the involvement of the noradrenergic system, dopaminergic and imidazoline receptors in the antidepressant-like effect of tramadol in mice.
abstract: The involvement of the noradrenergic system, imidazoline, dopaminergic and adenosinergic receptors in the antidepressant-like action of tramadol in the mouse forced swimming test (FST) was evaluated in this study. The antidepressant-like effect of tramadol (40mg/kg, per oral, p.o.) in the FST was blocked with yohimbine (1mg/kg, i.p., an alpha(2)-adrenoceptor antagonist), alpha-methyl-para-tyrosine methyl ester (AMPT, 100mg/kg, i.p., an inhibitor of tyrosine hydroxylase), efaroxan (1mg/kg, i.p., an imidazoline I(1)/alpha(2)-adrenoceptor antagonist), idazoxan (0.06mg/kg, i.p., an imidazoline I(2)/alpha(2)-adrenoceptor antagonist), antazoline (5mg/kg, i.p., a ligand with high affinity for the I(2) receptor), haloperidol (0.2mg/kg, i.p., a non selective dopamine receptor antagonist), SCH23390 (0.05mg/kg, subcutaneously, s.c., a dopamine D(1) receptor antagonist), sulpiride (50mg/kg, i.p., a dopamine D(2) and D(3) receptor antagonist) but was not reversed by prazosin (1mg/kg, intraperitoneally, i.p., an alpha(1)-adrenoceptor antagonist) and caffeine (3mg/kg, i.p., a nonselective adenosine receptor antagonist). Monoamine oxidase-A and -B (MAO-A and MAO-B) activities were neither inhibited in the whole brain nor in specific brain regions of mice treated with tramadol. These data demonstrated that the antidepressant-like effect caused by oral administration of tramadol in the mouse FST is mediated by the noradrenergic system, dopaminergic and imidazoline receptors.
authors.affiliation: Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, CEP 97105-900, RS, Brazil.
authors.forename: Cristiano R
authors.initials: CR
authors.lastname: Jesse
authors.forename: Ethel A
authors.initials: EA
authors.lastname: Wilhelm
authors.forename: Cristiani F
authors.initials: CF
authors.lastname: Bortolatto
authors.forename: Cristina W
authors.initials: CW
authors.lastname: Nogueira
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003863:Depression / Q000188:drug therapy / Q000523:psychology; D004305:Dose-Response Relationship, Drug; D054755:Imidazoline Receptors / Q000502:physiology*; D008297:Male; D051379:Mice; D009638:Norepinephrine / Q000502:physiology*; D011941:Receptors, Adrenergic / Q000502:physiology; D011954:Receptors, Dopamine / Q000502:physiology*; D014147:Tramadol / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000928:Antidepressive Agents; D054755:Imidazoline Receptors; D011941:Receptors, Adrenergic; D011954:Receptors, Dopamine; D014147:Tramadol; D009638:Norepinephrine