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Reye's syndrome: salicylates and mitochondrial functions
Biochemical Pharmacology
|September 15, 1984
Summary
Aspirin and related compounds, with calcium, damage mitochondria by increasing inner membrane permeability. This effect, particularly with salicylate, may contribute to Reye
Area of Science:
- Biochemistry
- Cell Biology
- Toxicology
Background:
- Mitochondria are crucial for cellular energy production.
- Oxidative metabolism in mitochondria is sensitive to various chemical agents.
- Calcium ions (Ca2+) play a role in mitochondrial function and dysfunction.
Purpose of the Study:
- To investigate the impact of aspirin (acetylsalicylate, ASA) and related compounds on isolated rat liver mitochondria in the presence of Ca2+.
- To elucidate the mechanism by which ASA and salicylates affect mitochondrial oxidative metabolism and membrane integrity.
- To explore the potential role of these effects in conditions like Reye's syndrome.
Main Methods:
- Studied isolated rat liver mitochondria incubated with aspirin (ASA) and Ca2+.
- Measured state 4 respiratory rates with NAD+-linked substrates and succinate.
- Utilized Ca2+-transport inhibitors (ruthenium red, EGTA) and NAD+.
- Assessed release of intramitochondrial NAD(P)+ to evaluate membrane permeability.
- Tested commercial aspirin brands and other salicyl derivatives.
Main Results:
- ASA + Ca2+ transiently stimulated, then inhibited, state 4 respiration with NAD+-linked substrates.
- Inhibition by ASA + Ca2+ was not reversed by ADP or uncoupler.
- Ca2+-transport inhibitors prevented ASA + Ca2+ effects.
- Salicylate was more potent than ASA; acetaminophen had minimal effect at comparable concentrations.
- Salicylate + Ca2+ increased mitochondrial inner membrane permeability, releasing NAD(P)+.
- Effects were dependent on Ca2+, salicylate concentrations, preincubation time, and inorganic phosphate.
- Rotenone prevented salicylate + Ca2+-induced mitochondrial damage, suggesting a role for pyridine nucleotide redox state.
Conclusions:
- Salicylate and related compounds potentiate Ca2+-induced damage to the mitochondrial inner membrane.
- This potentiation involves increased mitochondrial membrane permeability.
- The findings suggest a potential mechanism linking aspirin/salicylates, mitochondrial dysfunction, and Reye's syndrome.