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Voltage-activated proton current in eosinophils from human blood
D V Gordienko1, M Tare, S Parveen
1Department of Pharmacology and Clinical Pharmacology, St George's Hospital Medical School, London, UK.
The Journal of Physiology
|October 15, 1996
Summary
Human eosinophils exhibit voltage-dependent proton (H+) conductance. This proton current is modulated by intracellular calcium, arachidonic acid, and pH gradients, suggesting a role in eosinophil function.
Area of Science:
- Cellular electrophysiology
- Ion channel function
- Human eosinophil biology
Background:
- Eosinophils are key players in allergic inflammation.
- Their membrane potential and ion transport mechanisms are not fully understood.
- Understanding these properties is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the electrophysiological properties of human eosinophils.
- To characterize the ion conductance responsible for outward currents.
- To explore the regulation of this conductance by various cellular factors.
Main Methods:
- Whole-cell voltage-clamp recordings from freshly isolated human eosinophils.
- Manipulation of intracellular and extracellular ion concentrations and pH.
- Application of specific modulators like arachidonic acid and zinc ions.
- Assessment of the effects of varying intracellular calcium concentrations.
Main Results:
- Eosinophils possess a resting membrane potential of -63 mV.
- A voltage-dependent outward current, highly selective for H+ ions, was identified.
- This proton current is modulated by intracellular calcium, extracellular pH, and arachidonic acid.
- Zinc ions reversibly inhibited the proton current in a voltage-dependent manner.
Conclusions:
- Human eosinophils have a voltage-dependent proton conductance (gH).
- This conductance is regulated by intracellular calcium, pH, and arachidonic acid.
- These findings provide new insights into eosinophil electrophysiology and potential therapeutic targets.