Coarse-grained entropy rates quantify fast Ca~2+ dynamics modulated by pharmacological stimulation

摘要

Calcium (Ca~2+) is an ubiquitous intracellular messenger which regulates cellular processes, such as secretion, contraction, and cell proliferation~1,2. A variety of cell types respond to hormonal stimuli with periodic oscillations of the intracellular free Ca~2+ concentration ((Ca~2+_i) which can be modulated in theri frequency in a dosedependent manner. The period of these well-studied oscillations varies normally between 30 sec and a couple of minutes. Here we study (Ca~2+)_i oscillations in clonal beta cells (hamster insulin secreting cells, HIT) under pharmacological stimulation. Bedides the well-known high-amplitude low frequency oscillations we try to analyze for the first time low-lamplitude high frequency oscillations of (Ca~2+)_i under pharmacological stimulation which have not been explored in experimental approaches to date. Using coarse-grained entropy rates computed from information-theoretic functionals we demonstrate differences in temporal complexity of the fast lowamplitude (Ca~2+)_i dynamics corresponding to different phases of pharmacological stimulation which are additional to the well-knwon dose-dependent pattern of low-frequency high amplitude (Ca~2+)_i dynamics.