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In vivo and in vitro effects of the pineal gland and melatonin on [Ca 2+ + Mg 2+ ]‐dependent ATPase in cardiac sarcolemma
Author(s) -
Chen LiDun,
Tan DunXian,
Reiter Russel J.,
Yaga Ken,
Poeggeler Burkhard,
Kumar Pramod,
Manchester Lucien C.,
Chambers James P.
Publication year - 1993
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.1993.tb00500.x
Subject(s) - melatonin , sarcolemma , medicine , endocrinology , pinealectomy , pineal gland , atpase , biology , in vivo , enzyme assay , ouabain , circadian rhythm , pinealocyte , chemistry , enzyme , biochemistry , myocyte , sodium , microbiology and biotechnology , organic chemistry
The possible diurnal variation in cardiac [Ca 2+ + Mg 2+ ]‐dependent ATPase (Ca 2+ pump) activity and the influence of pinealectomy and melatonin on this enzyme in rat heart have been studied. Lowest levels of cardiac sarcolemma] membrane [Ca 2+ + Mg 2+ ]‐dependent ATPase activity were measured in late afternoon in rats kept under a 14:10 light:dark cycle. Late in the dark phase the enzyme activity began to increase with the rise continuing until 0900, 3 hr after light onset. These time‐dependent changes in [Ca 2+ + Mg 2+ ]‐dependent ATPase activity did not occur in either pinealectomized or light‐exposed rats suggesting that melatonin, secreted from the pineal gland during the night, induces the change in [Ca 2+ + Mg 2+ ]‐dependent ATPase activity. In vitro studies in which cardiac tissue was incubated in the presence of melatonin over a wide range of doses showed that this indole stimulated the Ca 2+ pump. The half‐maximal effect of melatonin was observed at a melatonin concentration of 28 ng/ml. These findings suggest that the daily change in [Ca 2+ + Mg 2+ ]‐dependent ATPase activity in the sarcolemma of heart tissue is a result of the circadian rhythm in pineal melatonin production and secretion. These findings may be applicable to normal cardiac physiology.