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Channel arrest: implications from membrane resistance in turtle neurons
C J Doll1, P W Hochachka, P B Reiner
1Department of Zoology, University of British Columbia, Vancouver, Canada.
The American Journal of Physiology
|November 1, 1991
Summary
Hypoxia-tolerant animals conserve energy via metabolic depression. This study found that turtles do not use "channel arrest," a proposed mechanism involving reduced ion leakage, to save energy during short-term anoxia.
Area of Science:
- Physiology
- Zoology
- Biochemistry
Background:
- Metabolic depression is a key survival strategy for animals facing low oxygen conditions (hypoxia).
- A potential mechanism for metabolic depression is "channel arrest," where ion leakage through plasma membranes decreases.
- This reduction in ion flux is hypothesized to conserve energy by lowering the demand on ATP-dependent ion pumps.
Purpose of the Study:
- To investigate whether "channel arrest" is employed by anoxia-tolerant animals for energy conservation.
- To test the channel arrest hypothesis in the anoxia-tolerant turtle (Chrysemys picta).
Main Methods:
- Intracellular recordings were performed on cortical slices from turtles.
- Whole-cell input resistance and specific membrane resistivity were measured.
- Measurements were taken under both normal (control) and anoxic conditions.
Main Results:
- No significant changes in membrane resistance were observed during anoxia.
- This indicates that ion leakage did not decrease in the turtle cortical slices.
Conclusions:
- The "channel arrest" mechanism was not utilized by the turtle for energy conservation during short-term anoxia (≤120 minutes).
- Alternative or additional mechanisms of metabolic depression may be employed by this species.