Brain cell microenvironment effects on neuron excitability and basal metabolism

Area of Science:

• Neuroscience
• Cellular Biology
• Computational Biology

Background:

• Neuronal function is intricately linked to the extracellular space (ECS) volume within the brain.
• Alterations in ECS volume can significantly affect neuronal excitability and cellular metabolism.
• Understanding these dynamics is crucial for comprehending brain function and dysfunction.

Purpose of the Study:

• To investigate the relationship between extracellular space volume fraction and neuronal excitability.
• To determine a general coefficient quantifying excitability changes in response to volume variations.
• To explore the role of chloride ions and metabolic rates in modulating these effects.

Main Methods:

• Development of a computational model of neurons within a brain cell assembly.
• Mathematical determination of a coefficient of excitability related to volume fraction.
• Simulations to analyze the impact of chloride and metabolic pumping rates on membrane stability.

Main Results:

• A widely applicable coefficient of excitability was determined, linking ECS volume fraction to neuronal excitability.
• Calculations indicate chloride ions enhance membrane stability by indirectly accelerating metabolic pumping when ECS volume decreases.
• Diminished extracellular volume fraction was shown to influence metabolic pumping rates.

Conclusions:

• Changes in extracellular space volume are a critical factor influencing neuronal excitability and brain metabolism.
• Chloride's role in stabilizing neuronal membranes under conditions of reduced extracellular volume has been elucidated.
• Volume fraction changes, particularly cell swelling, may contribute to epilepsy, cell death post-brain injury, and recovery processes.