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Comparison of the Rat Pinealocyte Ultrastructure With Melatonin Concentrations During Daytime and at Night
Author(s) -
Karasek M.,
Stankov B.,
Lucini V.,
Scaglione F.,
Esposti G.,
Mariani M.,
Fraschini F.
Publication year - 1990
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1990.tb00900.x
Subject(s) - melatonin , pinealocyte , pineal gland , ultrastructure , medicine , endocrinology , biology , daytime , golgi apparatus , endoplasmic reticulum , circadian rhythm , vacuole , cytoplasm , anatomy , microbiology and biotechnology , atmospheric sciences , geology
The aim of this study was to investigate the ultrastructure of rat pinealocyte during daytime (1600 h) and at night (0100 h) and to compare these observations with serum melatonin levels in the same animals. In addition, pineal melatonin concentrations were determined in other animals. Both serum and pineal melatonin concentrations were significantly higher at night than during daytime (34 and 21 times, respectively). Sizes of pinealocytes, their nuclei, and nucleoli, as well as cross‐sectional areas of mitochondria and granular endoplasmic reticulum were also higher at night than during daytime, whereas areas of lysosomes, Golgi apparatus, and vacuoles containing flocculent material did not differ at the time points studied. In contrast, the number of dense‐core vesicles was higher during daytime. The results of the present study show that morphological patterns of higher metabolic activity of the rat pinealocyte at night when compared to those during daytime correlate with melatonin concentrations.