Circadian variations in melatonin‐binding sites in discrete areas of the male rat brain

FEBS Letters

Laudon, Moshe¹  Nir, Isaac²  Zisapel, Nava¹ 

[1] Department of Biochemistry, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv Israel;Department of Pharmacology, Hebrew University-Hadassah Medical School, Jerusalem, Israel

关键词: Melatonin;    Iodomelatonin;    Binding site;    Circadian rhythm;    (Rat brain);   

DOI  :  10.1016/0014-5793(88)80411-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The binding of ¹²⁵I-melatonin to synaptosomes prepared from whole brains of male rats of the CD strain and from the brain, hypothalamus and striatum of male rats of the Sabra-Wistar strain was assessed throughout a 24 h period. The animals were maintained under a daily schedule of 14 h light (05:00–19:00 h) and 10 h darkness. In whole brain preparations the density of binding sites at 18:00 h was higher by about 70% than at 02:00 h with no variations in apparent affinity of the binding sites throughout the daily period. Specific binding of ¹²⁵I-melatonin was found in both hypothalamus and striatum of the male rat with a distinct diurnal variation in binding site density in the hypothalamus only. The density of ¹²⁵I-melatonin-binding sites in the hypothalamus was maximal between 10:00 and 18:00 h and dropped sharply after the lights went off. The apparent ¹²⁵I-melatonin-binding affinities in these regions were constant and very similar to those in whole brain preparations. The daily variations in densities of ¹²⁵I-melatonin-binding sites in discrete brain areas may represent a diurnal rhythmicity in the responsiveness of the neuroendocrine axis to melatonin.

【 授权许可】

Unknown