Related Experiment Videos
Inhibitory effects of gentamicin and ethacrynic acid on mammalian microsomal protein synthesis
Abstract:
The ototoxic antibiotic gentamicin, and the ototoxic diuretic ethacrynic acid, both produce inhibitory effects on protein synthesis in microsomes isolated from rat brain. Inhibitory effects appear to be essentially independent of each other. The inhibitory dose-response curve for gentamicin is logarithmic, while that for ethacrynic acid is linear. The dose-response curves make gentamicin the predominant inhibitor when the drugs are combined at low concentrations and ethacrynic acid the predominant inhibitor when the drugs are combined at high concentrations. Accumulation of aminoglycoside by tissues of the inner ear may result in inhibition of protein synthesis in spite of low and transient plasma levels of the drug. Further inhibition of translation by ethacrynic acid could account, in part, for the ototoxic interaction of aminoglycosides and high ceiling diuretics.
Insights
Gentamicin and ethacrynic acid inhibit protein synthesis in rat brain microsomes. Their combined effects depend on concentration, with gentamicin dominant at low doses and ethacrynic acid at high doses.
Area of Science:
- Neuroscience
- Pharmacology
- Toxicology
Background:
- Gentamicin, an antibiotic, and ethacrynic acid, a diuretic, are known ototoxic agents.
- Ototoxicity can manifest as hearing loss and balance problems.
- Both drugs have been implicated in protein synthesis inhibition.
Purpose of the Study:
- To investigate the effects of gentamicin and ethacrynic acid on protein synthesis in rat brain microsomes.
- To determine the dose-response relationship for each drug's inhibitory effect.
- To elucidate the interaction between gentamicin and ethacrynic acid on protein synthesis.
Main Methods:
- Isolation of microsomes from rat brain.
- Incubation of microsomes with varying concentrations of gentamicin and ethacrynic acid.
- Measurement of protein synthesis inhibition using established biochemical assays.
Main Results:
- Both gentamicin and ethacrynic acid inhibited protein synthesis in a concentration-dependent manner.
- Gentamicin exhibited a logarithmic dose-response curve, while ethacrynic acid showed a linear curve.
- At low concentrations, gentamicin was the predominant inhibitor; at high concentrations, ethacrynic acid predominated.
- The inhibitory effects of the two drugs were largely independent.
Conclusions:
- Gentamicin and ethacrynic acid independently inhibit protein synthesis in rat brain microsomes.
- The concentration-dependent interaction suggests a complex mechanism underlying their combined ototoxicity.
- Understanding these interactions is crucial for managing the ototoxic risks associated with co-administered aminoglycosides and high-ceiling diuretics.