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Oscillations of membrane potential in L cells. I. Basic characteristics
The Journal of Membrane Biology
|August 4, 1977
Summary
Giant L cells exhibit spontaneous membrane potential oscillations, which are blocked by cooling or metabolic inhibitors but not by electrical stimuli. This suggests a temperature-sensitive, metabolically dependent mechanism underlies these oscillations.
Area of Science:
- Cellular Electrophysiology
- Membrane Biophysics
Background:
- L cells, particularly large nondividing giant L cells, are a model for studying cellular electrical properties.
- Understanding the mechanisms of membrane potential regulation is crucial for cell physiology.
Purpose of the Study:
- To investigate the electrophysiological properties of L cells, focusing on spontaneous membrane potential oscillations.
- To determine the factors influencing these oscillations, including stimuli, temperature, and metabolic activity.
Main Methods:
- Standard electrophysiological techniques were employed to measure membrane potentials and resistances.
- Intracellular ion concentrations (K+, Na+, Cl-) were measured using flame photometry and a chloridometer.
- Cells were subjected to electrical and mechanical stimuli, cooling, and metabolic inhibitors.
Main Results:
- L cells displayed resting membrane potentials around -15 mV and resistances around 37 MΩ.
- Giant L cells exhibited spontaneous membrane potential oscillations between -15 and -40 mV.
- Spontaneous oscillations were abolished by cooling and metabolic inhibitors, while electrically induced hyperpolarizing responses persisted.
- Membrane conductance increased with hyperpolarizing responses.
Conclusions:
- Spontaneous membrane potential oscillations in L cells are dependent on cellular metabolism and temperature.
- Electrically induced hyperpolarizing responses appear to involve different mechanisms than spontaneous oscillations.
- These findings provide insights into the active and passive electrical properties of L cells.