ALTERATION OF BROWN ADIPOCYTE Ca2+ RESPONSES IN CULTURE
BY ADRENERGIC ACTIVATION
E. A. Turovsky, M. V. Konakov, A. V. Berezhnov, V. P. Zinchenko, G. E. Bronnikov, L. P. Dolgacheva
Institute of Cell Biophysics RAS, Pushchino, Moscow Region;
e-mail: Dolgacheva@mail.ru
Thermogenic capability of brown adipose tissue is controlled by norepinephrine. Interaction of norepinephrine
with adipocyte α1- and β-adrenergic receptors results in the increase of Ca2+ and cAMP concentrations. The
[Ca2+]i changes initiated by norepinephrine and selective agonists of α1- and β-adrenergic receptors, cirazolin
and isoproterenol, were recorded in single cells of primary culture on the 1st, 3rd and 6th days in vitro. On the
first day, isoproterenol-induced [Ca2+]i changes as compared to cirazolin-induced ones were characterized by
greater amplitude and lesser impulse duration over the entire range of physiological concentrations used. These
differences were negligible after 3 days and kinetic differences were practically absent after 6 days of cultivation.
The agonist-induced [Ca2+]i changes in proliferating and differentiated cells differed significantly: in the
process of cell growth in culture, the amplitude of calcium response increased, the duration of impulse signal
decreased and the sensitivity to adrenergic agonists increased. The Ca2+ store in endoplasmic reticulum increased
during the cell growth and development in culture, according to thapsigargin-induced Ca2+ response amplitude
increase in Ca2+ free medium. The rate of Ca2+ pumping out of cell characterizing PMCA-activity also increased.
Key words: brown preadipocytes, adrenergic receptors, intracellular Ca2+, primary culture
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