Maintenance of low sodium and high potassium levels in cells and in tendon/collagen

Mammalian cells have a higher concentration of potassium and a lower concentration of sodium than their extracellular environment. The mechanisms responsible for the unequal distribution of these ions are commonly ascribed to the presence of an energy requiring plasma membrane ATPase pump, and the p...

Full description

Saved in:
Bibliographic Details
Published in:Cell biology international 2012-06, Vol.36 (6), p.503-509
Main Authors: Cameron, Ivan L., Lanctot, Anthony C., Fullerton, Gary D.
Format: Article
Language:English
Subjects:
Achilles Tendon - anatomy & histology
Achilles Tendon - chemistry
Achilles Tendon - cytology
Achilles Tendon - metabolism
Animals
Cattle
Collagen - chemistry
Collagen - metabolism
Desiccation
ion distribution
Organ Size
Potassium - chemistry
Potassium - metabolism
Protein Binding
Sodium - chemistry
Sodium - metabolism
solute distribution
swelling water
tendon/collagen
water solvency
water-of-hydration
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Mammalian cells have a higher concentration of potassium and a lower concentration of sodium than their extracellular environment. The mechanisms responsible for the unequal distribution of these ions are commonly ascribed to the presence of an energy requiring plasma membrane ATPase pump, and the presence of membrane channels that pass one ion selectively, while excluding others. This report deals with other mechanisms that might explain this heterogeneous distribution of ions. To study other mechanisms, we turned to a non‐living system, specifically tendon/collagen to eliminate the contribution of the membrane pump and channels. A simple gravimetric method was designed to measure solute accumulation or exclusion during rehydration of a well‐washed, carefully dried and well‐characterized protein specimen (tendon/collagen). Exposure to physiological salt concentrations resulted in selective exclusion of Na+ over K+, whereas exposure to low‐salt concentration resulted in accumulation of these solutes. It is postulated that this solute redistribution occurs in all hydrated proteins and is partially responsible for the heterogeneous solute distribution in cells presently assigned to pump and channel mechanisms. Physical and thermodynamic mechanisms are offered to explain the observed heterogeneous solute distributions.
ISSN:1065-6995
1095-8355
DOI:10.1042/CBI20110439