Circadian rhythm in the number of granulated vesicles in the pinealocytes of mice. Effects of sympathectomy and melatonin treatment

Cell and Tissue Research
B Benson, M Krasovich


Adult, Charles River CD-1, male mice were housed in an environmental control chamber under strict conditions of controlled light (12D/12L) and temperature. The mice were sacrificed at various times throughout the twenty-four hour clock and their pineals prepared routinely for electron microscopy. The number of dense-cored or granulated vesicles present in the polar terminals of pinealocytes were quantitated in thin cross sections through pericapillary areas. A distinct circadian rhythm was observed in the number of granulated vesicles with a three- to four-fold difference between late photoperiod maximum and late dark period minimum. The rhythm was abolished by bilateral superior cervical ganglionectomy. These results are consistent with the hypothesis that the granulated vesicles are synthesized and stored in the pinealocytic cytoplasm during the photoperiod under the tropic influence of norepinephrine, and are released during the dark period when melatonin synthesis is greatest. Melatonin, administered as daily intraperitoneal doses of 50 microgram over a period of five days, was observed to increase markedly the number of pinealocytic granulated vesicles during the light period, but led during the dark period to a decrease i...Continue Reading


Jan 1, 1983·Psychoneuroendocrinology·P Pevet
May 1, 1990·Journal of Gastroenterology and Hepatology·Y Uchiyama
Jan 1, 1991·Journal of Pineal Research·H E ChuluyanD P Cardinali
Jan 1, 1988·Journal of Pineal Research·Y Satoh, L Vollrath
Aug 15, 2018·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Juan C MayoRosa M Sáinz
Apr 1, 1992·Microscopy Research and Technique·K P Bhatnagar
Apr 1, 1992·Microscopy Research and Technique·M Karasek, R J Reiter
Dec 1, 1981·The American Journal of Anatomy·R J Reiter

Related Concepts

Circadian Rhythms
Mice, Inbred Strains
Pineal Gland
Mouse, Swiss

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