Effects of subchronic administration of psychoactive substances on the circadian rhythm of urinary corticosterone excretion in rats.
Abnormal function of the hypothalamo-pituitary-adrenocortical (HPA) axis has been observed in depressed patients. Experiments with laboratory rats were performed to test whether psychoactive substances (among them clinically effective antidepressants) influence circadian HPA activity. For this purpose, corticosterone was measured in urine collected for 24 h at 4 h intervals. Maprotiline, fluoxetine, imipramine, trimipramine, clorgyline and pargyline were given once daily for at least 13 days, by either intraperitoneal or subcutaneous (clorgyline) injection. Only two substances produced significant changes in the circadian pattern of corticosterone excretion: pargyline distinctly delayed the phase of circadian HPA activity, and trimipramine prolonged the nocturnal increase in urinary corticosterone. The present results suggest that psychoactive drugs have no effects in common on the circadian rhythm of HPA activity in rats.
D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects*; D003010:Clorgyline / Q000494:pharmacology; D003345:Corticosterone / Q000652:urine*; D005473:Fluoxetine / Q000494:pharmacology*; D007099:Imipramine / Q000494:pharmacology; D008297:Male; D008376:Maprotiline / Q000494:pharmacology; D010293:Pargyline / Q000494:pharmacology; D011437:Propylamines / Q000494:pharmacology*; D051381:Rats; D014299:Trimipramine / Q000494:pharmacology
D000928:Antidepressive Agents; D011437:Propylamines; D005473:Fluoxetine; D008376:Maprotiline; D014299:Trimipramine; D010293:Pargyline; D003010:Clorgyline; D007099:Imipramine; D003345:Corticosterone