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Abnormalities of cell volume regulation and their functional consequences
The American Journal of Physiology
|September 1, 1980
Summary
Body fluid osmolality disturbances cause central nervous system dysfunction. The brain protects its volume by generating new solutes in hyperosmolal states and losing electrolytes in hyposmolal states.
Area of Science:
- Nephrology
- Neuroscience
- Cell Physiology
Background:
- Disturbances in body fluid osmolality, both hyperosmolal and hyposmolal states, are common clinical issues.
- Central nervous system dysfunction is the primary manifestation of these osmolality imbalances.
Purpose of the Study:
- To elucidate the brain's response to hyperosmolal and hyposmolal states.
- To understand the mechanisms of brain volume regulation and adaptation.
Main Methods:
- The study reviews the physiological responses of brain tissue to altered extracellular osmolality.
- It examines the role of intracellular solute generation and electrolyte loss in volume regulation.
Main Results:
- In hyperosmolal states, the brain initially shrinks but can restore volume via endogenous solute generation (idiogenic osmoles), but not with exogenous solutes like mannitol.
- In hyposmolal states, the brain expands less than other tissues, later restoring volume by losing intracellular electrolytes and solutes.
Conclusions:
- The brain employs distinct mechanisms to protect its volume in response to osmolality disturbances.
- These adaptive strategies, involving solute and electrolyte shifts, significantly alter intracellular composition and brain function.