Related Experiment Videos
Sustained depolarization and ADP-ribose activate a common ionic current in rat peritoneal macrophages
Brice Campo1, Annmarie Surprenant, R Alan North
1Institute of Molecular Physiology, University of Sheffield, Sheffield, United Kingdom.
Journal of Immunology (Baltimore, Md. : 1950)
|January 23, 2003
Summary
Phagocytosis causes macrophage membrane potential changes. Prolonged depolarization activates a nonselective ion conductance, likely mediated by ADP-ribose, impacting macrophage function.
Area of Science:
- Cellular electrophysiology
- Macrophage biology
- Ion channel function
Background:
- Phagocytosis induces significant macrophage membrane potential shifts.
- The functional role of these membrane potential changes remains unclear.
Purpose of the Study:
- To investigate the functional significance of membrane potential changes during phagocytosis in macrophages.
- To characterize the ion conductance activated by sustained depolarization.
Main Methods:
- Whole-cell patch-clamp recordings from rat peritoneal macrophages.
- Electrophysiological analysis of ion current properties, including voltage dependence and ion selectivity.
- Investigation of the effects of intracellular and extracellular modulators on the activated conductance.
Main Results:
- Sustained depolarization (>30 s) activated a nonselective ion conductance.
- This conductance was voltage-dependent, reversed near 0 mV, and was permeable to N-methyl-D-glucamine, chloride, and calcium.
- Intracellular ATP/ADP and extracellular lanthanum blocked the current, while intracellular ADP-ribose or beta-NAD activated it.
Conclusions:
- Prolonged macrophage depolarization leads to increased intracellular ADP-ribose levels.
- ADP-ribose activates a nonselective ion conductance, suggesting a novel regulatory mechanism in macrophages.