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F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes
Published on: May 4, 2013
ATP-activated Ca(2+)-permeable channels in rat peritoneal macrophages
A P Naumov1, Y A Kuryshev, E V Kaznacheyeva
1Institute of Cytology of Russian Academy of Sciences, St. Petersburg.
FEBS Letters
|November 30, 1992
Summary
Extracellular adenosine triphosphate (ATP) activates cation channels in rat macrophages, facilitating calcium (Ca2+) influx. A GTP-binding protein appears to mediate this ATP-induced channel activity and calcium entry.
Area of Science:
- Cellular physiology
- Ion channel function
- Macrophage biology
Background:
- Adenosine triphosphate (ATP) acts as an extracellular signaling molecule.
- Calcium (Ca2+) influx plays a critical role in macrophage activation and function.
- Mechanisms of ATP-mediated ion transport in macrophages require further elucidation.
Purpose of the Study:
- To investigate the mechanisms underlying adenosine triphosphate (ATP)-induced calcium (Ca2+) influx in rat peritoneal macrophages.
- To characterize the ion permeability and gating properties of ATP-activated channels.
- To explore the potential involvement of G-protein coupled pathways in ATP-induced cation influx.
Main Methods:
- Utilized the patch-clamp technique, including whole-cell and cell-attached configurations.
- Applied extracellular ATP to stimulate macrophages.
- Performed ion substitution experiments to determine channel selectivity.
- Investigated channel gating with non-hydrolyzable GTP analogues.
Main Results:
- Extracellular ATP activated channels permeable to both divalent (Ca2+, Sr2+, Mn2+, Ba2+) and monovalent (Na+) cations.
- Unitary channel conductances varied significantly across different cations, indicating selective permeability.
- Channel activation was observed in the presence of non-hydrolyzable GTP analogues, suggesting G-protein involvement.
- Data support the role of a GTP-binding protein in coupling ATP receptors to channel activation.
Conclusions:
- Extracellular ATP triggers the opening of cation-selective channels in rat peritoneal macrophages.
- These channels are crucial for mediating ATP-induced calcium influx.
- A GTP-binding protein is implicated in the signaling pathway linking ATP receptor activation to channel gating.
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