Effects of antibiotics on the contractility and Ca2+ transients of rat cardiac myocytes.
We have compared the effects of streptomycin sulphate, gentamicin sulphate and neomycin sulphate on cell shortening (our index of contractility) and intracellular Ca2+ ([Ca2+](i)) transients of rat ventricular myocytes. All three agents abolished shortening and [Ca2+](i), transients but streptomycin was significantly less potent than the other agents. The IC(50) of streptomycin was 0.37 mM for shortening and 0.78 mM for [Ca2+](i), approximately an order of magnitude greater than equivalent values for gentamicin and neomycin. Gentamicin and streptomycin shortened the action potential duration of most cells but prolonged the action potential duration of others. We therefore conclude that multiple ionic mechanisms affecting action potential duration are modulated by these antibiotics. Our observations are consistent with the negative inotropic effect of antibiotics being caused by a decrease in Ca2+ influx causing a reduction in the [Ca2+](i) transient.
Belus
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A
School of Biomedical Sciences, University of Leeds, LS2 9JT, Leeds, UK.
White
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E
D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005839:Gentamicins / Q000494:pharmacology; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000166:cytology; D009355:Neomycin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013307:Streptomycin / Q000494:pharmacology; D016276:Ventricular Function
D000900:Anti-Bacterial Agents; D015220:Calcium Channels; D005839:Gentamicins; D009355:Neomycin; D002118:Calcium; D013307:Streptomycin