Effect of different photoperiods on the diurnal rhythm of 5-methoxytryptamine in the pineal gland of golden hamsters (Mesocricetus auratus).
This study tested the photo-dependency of the rhythmic synthesis of 5-methoxytryptamine (5-MT) in the pineal gland of golden hamsters. After pargyline administration, pineal 5-methoxytryptamine and melatonin were measured by HPLC in male golden hamsters kept under short and long photoperiod. In both photoperiodic regimes, a clear 5-MT rhythm was observed which fitted a sinusoidal function with high values occurring during the daytime and low values occurring during the night-time. The duration of the low night-time levels was clearly proportional to the length of the dark phase. A marked rhythm of melatonin synthesis was also seen with low daytime levels and high night-time values. An inverse relationship between 5-MT and melatonin levels was observed. Thus, after pargyline administration, the rhythms of 5-MT and melatonin in the pineal gland of golden hamsters are photoperiod-dependent and show a reciprocal relationship.
Raynaud
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F
CNRS-URA 1332, Université Louis Pasteur, Strasbourg, France.
Pévet
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P
D008735:5-Methoxytryptamine / Q000096:biosynthesis*; D000818:Animals; D002940:Circadian Rhythm / Q000528:radiation effects*; D006224:Cricetinae; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D008297:Male; D008550:Melatonin / Q000096:biosynthesis; D008647:Mesocricetus / Q000502:physiology*; D010293:Pargyline / Q000494:pharmacology; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D012726:Sexual Behavior, Animal / Q000528:radiation effects; D013268:Stimulation, Chemical
D008735:5-Methoxytryptamine; D010293:Pargyline; D008550:Melatonin