Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 1: Systems and Network Biophysics
BP 1.6: Talk
Monday, March 18, 2024, 11:15–11:30, H 0112
Nonrenewal spiking in Calcium signaling — •Lukas Ramlow1,2,3, Martin Falcke2,3, and Benjamin Lindner1,2 — 1Bernstein Center for Computational Neuroscience, Berlin, Germany — 2Department of Physics, Humboldt University, Berlin, Germany — 3Max Delbrück Center for Molecular Medicine, Berlin, Germany
Inositol 1,4,5-trisphosphate-induced Ca2+ signaling is a second messenger system used by almost all eukaryotic cells. The agonist concentration that stimulates Ca2+ signaling is encoded in the sequence of Ca2+ concentration spikes. In response to the onset of stimulation, the times between spikes, the interspike intervals (ISIs), exhibit a distinct transient during which they gradually increase. In the steady state, this slow adaptation correlates the intervals and spiking is a nonrenewal process. We propose a stochastic model that can reproduce both stationary and transient statistics of experimentally observed ISI sequences. We derive approximate analytical expressions for the stationary ISI statistics and consider the response to the onset of a constant stimulus to estimate the length of the transient and the strength of the adaptation of the ISI. We show that the adaptation determines the coefficient of variation, in agreement with current ideas derived from experiments. Finally, we fit our model to reproduce the transient statistics of experimentally observed ISI sequences in stimulated HEK cells. The fitted model is able to qualitatively reproduce the relationship between stationary interval correlations and transient interval statistics.
Keywords: Calcium Signaling; Stochastic Processes; Nonlinear Dynamics