Volume transmission and its different forms in the central nervous system

Area of Science:

• Neuroscience
• Cellular Communication
• Extracellular Signaling

Background:

• Volume transmission (VT) is a widespread intercellular communication mode.
• VT occurs in extracellular fluid (ECF) and cerebrospinal fluid (CSF), differing from private wiring transmission (WT) in speed and channel structure.
• The extracellular space and matrix are key substrates for VT.

Purpose of the Study:

• To elucidate the mechanisms and scope of volume transmission in the central and peripheral nervous systems.
• To highlight the role of VT in both local and long-distance signaling, including synaptic and extrasynaptic communication.
• To explore novel aspects of VT, such as extracellular vesicle release and potential roles in behavior and disease.

Main Methods:

• Review and synthesis of existing literature on volume transmission.
• Analysis of experimental evidence for VT in various brain regions and the peripheral nervous system.
• Investigation of molecular and fluid dynamics involved in VT.

Main Results:

• VT involves diffusion and convection through the extracellular space, contrasting with the private channels of WT.
• Extrasynaptic VT links synaptic transmission, influencing glial cells and adjacent synapses, with evidence in human striatum for dopamine VT.
• Long-distance VT occurs via peptide and CSF flow, with indications for beta-endorphin and oxytocin; extracellular vesicles represent a 'Roamer' subtype of VT.

Conclusions:

• Volume transmission is a fundamental and versatile mode of intercellular communication in the nervous system.
• VT plays roles in synaptic plasticity, behavior (e.g., monogamy via oxytocin), and potentially in the spread of neurodegenerative diseases.
• VT is also relevant in the peripheral nervous system and may be modulated by practices like acupuncture.