title: Seasonal and circadian variations of behavioural response to antidepressants in the forced swimming test in rats.
abstract: In order to verify whether the variability reported to occur in the effectiveness of antidepressants in the forced swimming test (FST) was due to seasonal and/or circadian variations, the anti-immobility effect induced by several antidepressants was assessed in rats every month throughout the year or every 4 hours for 2 consecutive days. Amineptine (20 mg/kg), amitriptyline (15 mg/kg), desipramine (20 mg/kg), imipramine (15 mg/kg) and mianserin (15 mg/kg) exerted the maximal effect in March. The effect of nomifensine (5 mg/kg) was constant throughout the year. Unlike imipramine and mianserin, nomifensine induced an anti-immobility effect that was maximal during the light phase of the light/dark cycle and was constant in continuous darkness.
authors.affiliation: "Menarini Ricerche Sud", Via Tito Speri 10, 00040 Pomezia Roma, Italy Correspondence to F. Borsini: Present address: Instituto De Angeli, Via Serio 15, 20138 Milan Italy.
authors.forename: F.
authors.initials: F
authors.lastname: Borsini
authors.forename: A.
authors.initials: A
authors.lastname: Lecci
authors.forename: M.A.
authors.initials: MA
authors.lastname: Stasi
authors.forename: M.
authors.initials: M
authors.lastname: Pessia
authors.forename: A.
authors.initials: A
authors.lastname: Meli