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Updated: Jun 25, 2025
08:02
Isolation of Pulmonary Artery Smooth Muscle Cells from Neonatal Mice
Published on: October 19, 2013
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Superoxide Anions Inhibit Intracellular Calcium Response in Porcine Airway Smooth Muscle Cells
Ramesh Krishnan1, Mathur S Kannan2, Deepak A Deshpande3
1Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee.
AJP Reports
|May 24, 2024
Summary
Superoxide anions (O 2 - ) impair airway smooth muscle cell function by reducing intracellular calcium ([Ca 2+ ] i ) release and reuptake. This suggests superoxide may interfere with normal physiological processes in the airways.
Area of Science:
- Pulmonary Physiology
- Cellular Biology
- Biochemistry
Background:
- Superoxide anions (O 2 - ) significantly impact pulmonary parenchyma, affecting cell proliferation, metabolism, and airway smooth muscle (ASM) contraction.
- Intracellular calcium ([Ca 2+ ] i ) concentration is crucial for regulating ASM contraction, relaxation, proliferation, and gene expression.
Purpose of the Study:
- To investigate the impact of superoxide anions (O 2 - ) on agonist-stimulated intracellular calcium ([Ca 2+ ] i ) changes in airway smooth muscle (ASM) cells.
- To elucidate the role of O 2 - in regulating calcium handling mechanisms within ASM cells.
Main Methods:
- Freshly isolated porcine ASM (PASM) cells were loaded with Fura-2 AM to measure intracellular calcium ([Ca 2+ ] i ).
- Cells were exposed to xanthine and xanthine oxidase (X+XO) to generate O 2 - , with or without superoxide dismutase (SOD) pre-treatment.
- Calcium responses to agonists like acetylcholine (ACh), histamine, endothelin, caffeine, and thapsigargin (TPG) were measured in the presence or absence of extracellular Ca 2+ .
Main Results:
- Xanthine/xanthine oxidase (X+XO) exposure generated superoxide anions (O 2 - ), confirmed by inhibition with superoxide dismutase (SOD).
- Pre-incubation with X+XO significantly inhibited net intracellular calcium ([Ca 2+ ] i ) responses to ACh, histamine, caffeine, and TPG.
- SOD pre-treatment mitigated the inhibitory effects of X+XO on ACh-induced calcium elevation, confirming the role of O 2 - .
- X+XO treatment also reduced caffeine- and TPG-induced calcium elevation, indicating an effect on both calcium release and reuptake mechanisms.
Conclusions:
- Superoxide anions (O 2 - ) attenuate intracellular calcium ([Ca 2+ ] i ) release and reuptake in airway smooth muscle (ASM) cells.
- These findings suggest that superoxide may interfere with the normal physiological functions of ASM cells, potentially impacting airway responsiveness.
Keywords:
airway smooth muscle cellintracellular calciumlung illnessesoxidativesuperoxidesuperoxide dismutaseMore Related Videos
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