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Astrocytic processes: from tripartite synapses to the active milieu.
Alexey Semyanov1, Alexei Verkhratsky2
1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia.
Trends in Neurosciences
|September 4, 2021
Summary
This study introduces the "active milieu" concept, unifying nervous tissue components into a dynamic system. It highlights astrocytic processes
Area of Science:
- Neuroscience
- Cellular Biology
- Glial Biology
Background:
- The nervous tissue comprises diverse cellular and non-cellular components.
- Astrocytes, a type of glial cell, play crucial roles in brain function.
- Understanding the integrated function of nervous tissue components is essential.
Purpose of the Study:
- To introduce and define the concept of the 'active milieu'.
- To elucidate the role and structure of astrocytic processes within this milieu.
- To propose a homology between astrocytic leaflets and neuronal dendritic spines.
Main Methods:
- Conceptual framework development.
- Analysis of astrocytic process morphology (branches and leaflets).
- Comparative analysis with neuronal structures (dendritic shafts and spines).
Main Results:
- The 'active milieu' unifies neuronal, glial, extracellular, and vascular components.
- Astrocytic processes are classified into organelle-containing branches and organelle-free leaflets.
- Astrocytic branches with leaflets are proposed as homologous to dendritic shafts with spines.
Conclusions:
- Astrocytic processes are integral to the dynamic information processing of the active milieu.
- Astrocytic processes engage in reciprocal interactions with neuronal compartments.
- Astrocytic processes communicate with other nervous tissue elements within the active milieu.
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