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Calcium-activated calcium permeability in parathyroid cells.
FEBS Letters
|September 1, 1986
Summary
Lanthanum (La3+) activates calcium (Ca2+) permeability in parathyroid cells by binding to the cell surface. This suggests a novel Ca2+ receptor mechanism, distinct from direct Ca2+ interaction.
Area of Science:
- Cell biology
- Biochemistry
- Physiology
Background:
- Parathyroid cells regulate calcium homeostasis.
- The calcium-sensing receptor (CaSR) is crucial for this regulation.
- Understanding Ca2+ flux mechanisms is vital for parathyroid function.
Purpose of the Study:
- To investigate the mechanism of Ca2+ receptor in parathyroid cells.
- To explore the role of Lanthanum (La3+) as a probe for Ca2+ permeability.
- To elucidate the interaction between La3+ and Ca2+ in parathyroid cell signaling.
Main Methods:
- Utilized La3+ as a probe for cell surface binding.
- Measured 45Ca fluxes across the parathyroid cell membrane.
- Assessed cytoplasmic Ca2+ concentration (Ca2+i) changes.
Main Results:
- La3+ binds to the parathyroid cell surface without intracellular penetration.
- La3+ stimulates Ca2+ permeability, increasing Ca2+i.
- The effects of La3+ and extracellular Ca2+ on Ca2+i were not additive.
Conclusions:
- A novel Ca2+ permeability pathway exists in parathyroid cells.
- This pathway is physiologically activated by extracellular Ca2+ binding to an external receptor.
- La3+ serves as a valuable tool to study this Ca2+ receptor mechanism.