Clorgyline effect on pineal melatonin biosynthesis in rats with lesioned suprachiasmatic nuclei

  • G. F. Oxenkrug
  • P. J. Requintina
Conference paper
Part of the Journal of Neural Transmission. Supplement book series (NEURAL SUPPL, volume 52)


We have reported that clorgyline-induced stimulation of pineal melatonin biosynthesis could be augmented by the exposure to 24 h of constant light in young but not in aged rats. Aging is associated with the declined integrity of the suprachiasmatic nuclei (SCN), the major station of the light signal passage from the retina to the pineal gland. The present study aimed to investigate whether SCN integrity is essential for clorgyline effects on pineal melatonin biosynthesis in light-primed rats. Clorgyline (2.5mg/kg, s.c.) was administered to sham-operated and SCN-lesioned Sprague-Dawley rats kept under regular light/dark cycle or exposed to 24 h of constant light. Pineal melatonin and related indoles were evaluated by HPLC-fluorimetric procedure.

Clorgyline stimulated pineal melatonin biosynthesis in both SCN-lesioned and sham-operated rats kept under regular light/dark cycle. Exposure to constant light (for 24 h) augmented clorgyline-induced stimulation of melatonin biosynthesis in sham-operated rats, but not in SCN-lesioned animals. The obtained results suggest that decline in SCN activity (e.g., age-associated) might contribute to previously reported attenuation of clorgyline-induced stimulation of melatonin biosynthesis in light-primed aged rats.


Pineal Gland Suprachiasmatic Nucleus Melatonin Level Pineal Melatonin Prog Neuropsychopharmacol Biol Psychiatry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. McIntyre IM, Oxenkrug GF (1991) Effect of aging on melatonin biosynthesis induced by 5-hydroxytrytophan and constant light in rats. Prog Neuropsychopharmacol Biol Psychiatry 15: 561–566PubMedCrossRefGoogle Scholar
  2. Oxenkrug GF (1991) The acute effect of monoamine oxidase inhibitors on serotonin conversion to melatonin. In: Cooper A, Sandler M, Harnett S (eds): 5-Hydroxytryptamine and mental illness. Oxford University Press, Oxford New York Tokyo, pp 99–108Google Scholar
  3. Oxenkrug GF, Mclntyre IM, Requintina PJ, Duffy JD (1991) The response of the pineal melatonin biosynthesis to the selective MAO-A inhibitor, clorgyline, in young and middle-aged rats. Prog Neuropsychopharmacol Biol Psychiatry 15: 895–902PubMedCrossRefGoogle Scholar
  4. Pickard GE, Turek FW (1982) Splitting of the circadian rhythm of activity is abolished by unilateral lesions of the suprachiasmatic nuclei. Science 215: 1119–1121PubMedCrossRefGoogle Scholar
  5. Rietveld WJ (1992) The suprachiasmatic nucleus and other pacemakers. In: Touitou Y, Haus E (eds) Biologic rhythms in clinical and laboratory medicine. Springer, New York, pp 55–64CrossRefGoogle Scholar
  6. Satinoff E, Li H, Tcheng TC, Liu C, McArthur AJ, Medanic M, Gillette MU (1993) Do the suprachiasmatic nuclei oscillate in old rats as they do in young ones? Am J Physiol 265: R1216–R1222PubMedGoogle Scholar

Copyright information

© Springer-Verlag Wien 1998

Authors and Affiliations

  • G. F. Oxenkrug
    • 1
    • 2
  • P. J. Requintina
    • 1
  1. 1.Department of Psychiatry and Pineal Research LaboratorySt. Elizabeth’s Medical Center of Boston/Tufts UniversityBostonUSA
  2. 2.Department of PsychiatrySt. Elizabeth’s Medical CenterBostonUSA

Personalised recommendations