Tricyclic imipramine modification of the circadian rhythms of hypothalamic serotonin, its precursors and acid catabolite in individually housed rats.
Circadian rhythms of serotonin (5HT), its precursors tryptophan (TP) and 5-hydroxy-tryptophan (5HTP) and its acid catabolite 5-hydroxy-indoleacetic acid (5HIAA), were determined in the hypothalamus of control rats and rats which had been treated continuously with subcutaneous imipramine (10 mg/kg/day) for 2 weeks. Rats were individually housed and entrained to LD 12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between 5HT and 5HIAA rhythms. Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic 5HT and TP concentrations.
Greco
A M
AM
Institute of Human Physiological Sciences, Second Medical School, University of Naples, Italy.
Gambardella
P
P
Sticchi
R
R
D'Aponte
D
D
de Franciscis
P
P
D006916:5-Hydroxytryptophan / Q000378:metabolism; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007099:Imipramine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012701:Serotonin / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; D006916:5-Hydroxytryptophan; D007099:Imipramine