title: Circadian activity rhythms in hamsters and rats treated with imipramine in the drinking water.
abstract: Circadian rhythms of locomotor activity were recorded in 15 male golden hamsters and in 15 rats. The animals were exposed alternatingly to a variety of conditions with either light-dark cycles (LD) or continuous illumination (LL). The hamsters were split into two groups: 7 animals received plain water, and 8 animals water together with imipramine hydrochloride. The rats received plain water or water with imipramine in alternation. In all animals the addition of imipramine resulted in a reduction of water uptake and in a concomitant reduction of the daily amount of activity. Otherwise, no significant effects of imipramine could be observed: in LD, the phase-angle differences between rhythm and zeitgeber were not changed by imipramine, and, in the hamsters, the upper limits of entrainability and the rates of re-entrainment were identical in the two groups of animals; in LL, the period of the free-running rhythm was slightly lengthened by imipramine in the hamsters, but remained unchanged in the rats.
authors.affiliation: Max-Planck Institut für Verhaltensphysiologie, Andechs, Federal Republic of Germany.
authors.forename: J
authors.initials: J
authors.lastname: Aschoff
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D006224:Cricetinae; D003624:Darkness; D007099:Imipramine / Q000008:administration & dosage / Q000494:pharmacology*; D008027:Light; D008297:Male; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012621:Seasons
chemical_list: D007099:Imipramine