Astrocyte calcium signaling: Interplay between structural and dynamical patternsстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 6 декабря 2018 г.
Аннотация:Inspired by calcium activity in astrocytes, which is different in the cell body and thick branches on the one hand and thin branchlets and leaflets on the other hand, we formulate a concept of spatially partitioned oscillators. These are inhomogeneous media with regions having different excitability properties, with a global dynamics governed by spatial configuration of such regions. Due to a high surface-to-volume ratio, calcium dynamics in astrocytic leaflets is dominated by transmembrane currents, while somatic calcium dynamics relies on exchange with intracellular stores, mediated by IP3, which is in turn synthesized in the space nearby the plasma membrane. Reciprocal coupling via diffusion of calcium and IP3 between the two regions makes the spatial configuration an essential contributor to overall dynamics. Due to these features, the mechanisms governing the pattern formation of calcium dynamics differ from classical excitable systems with noise or from networks of clustered oscillators. We show how geometrical inhomogeneity can play an ordering role allowing for stable scenarios for calcium wave initiation and propagation.
Spatiotemporal dynamics of intracellular calcium is the most acknowledged feature of astrocytic behavior, whether at a single cell level or in a network. Recent data on astrocyte morphology and calcium transients create a basis to revise the existing computational models accounting for two distinct classes of astrocyte processes. While the soma and primary branches are well excitable, it is a dense mesh of fine processes that external stimuli reach first. Such spatial organization and specialization play a role in spatiotemporal patterns of intracellular calcium release. We introduced a concept of a spatially partitioned oscillator; its dynamics is governed by the spatial configuration of astrocyte processes. To analyze the theoretical implications of such organization, we designed several spatial templates and show that spatial heterogeneity provides a stable scenario for calcium wave discharges.