title: Clonidine potentiates the effects of tranylcypromine, phenelzine and two analogues in the forced swimming test in mice.
abstract: OBJECTIVE
  To compare tranylcypromine (TCP) and phenelzine (PLZ), two well-established inhibitors of monoamine oxidase (MAO), and 2 of their analogues, 4-fluorotranylcypromine (FTCP) and N2-acetylphenelzine (AcPLZ) respectively, with regard to effects in the forced swimming test, a behavioural test used to screen for potential antidepressant drugs.
  
  
  METHODS
  Mice were dropped individually into glass cylinders containing water. The duration of their immobility was scored during the last 4 minutes of the test.
  
  
  RESULTS
  Except for TCP at high doses, none of the drugs demonstrated activity when administered alone. All 4 drugs were active when given in combination with clonidine, an effect thought to be the result of mixed action at 5-HT1A and 5-HT2 receptors and the noradrenergic system. 5-HT18 receptors do not seem to be implicated, as lithium did not potentiate the effect of any of the drugs. Quinine activation of AcPLZ suggests that this analogue acts on 5-HT3 receptors.
  
  
  CONCLUSIONS
  FTCP and AcPLZ demonstrated anti-immobility activity in the forced swimming test when used in association clonidine. These findings confirm previous neurochemical findings suggesting that these drugs have antidepressant properties.
authors.affiliation: Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alta. mbourin@sante.univ-nantes.fr
authors.forename: Michel
authors.initials: M
authors.lastname: Bourin
authors.forename: Martine
authors.initials: M
authors.lastname: Hascoët
authors.forename: Marie Claude
authors.initials: MC
authors.lastname: Colombel
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Coutts
authors.forename: Glen B
authors.initials: GB
authors.lastname: Baker
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D003000:Clonidine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D008094:Lithium / Q000494:pharmacology; D008297:Male; D051379:Mice; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D010624:Phenelzine / Q000494:pharmacology*; D011803:Quinine / Q000494:pharmacology; D013550:Swimming / Q000523:psychology; D014191:Tranylcypromine / Q000494:pharmacology*
chemical_list: D000316:Adrenergic alpha-Agonists; D000928:Antidepressive Agents; D008996:Monoamine Oxidase Inhibitors; D014191:Tranylcypromine; D008094:Lithium; D011803:Quinine; D003000:Clonidine; D010624:Phenelzine