A study of the mechanism of action of aminoglycoside antibiotics on the guinea pig vas deferens.
Aminoglycoside antibiotics inhibit contractility of the isolated guinea pig vas deferens in a dose-related manner. However, total inhibition of the contractility cannot be attained, a phenomenon most probably attributed to the partial inhibition of the function of Ca channels by the antibiotics. The inhibitory potency of aminoglycoside antibiotics was found to be: sisomicin greater than gentamicin greater than netilmicin greater than streptomycin greater than dactimicin greater than amikacin greater than kanamycin greater than kanendomycin greater than dibekacin greater than tobramycin. Ca2+ antagonize the action of aminoglycoside antibiotics on the vas deferens competitively. This observation indicates that the untoward effect of aminoglycoside antibiotics on contractility of the vas deferens can be attributed to their ability to interfere with Ca2+ entry through cell membranes of the tissue, a prerequisite for subsequent contraction. Above a specific threshold (7.5 mM) Ca2+ have a prophylactic effect on vas deferens and prevent the inhibitory action of ICmax doses of the antibiotics. Thus, Ca could be used as a prophylactic medium or as an antidote in restoring contractility of the vas deferens if it is inhibited by aminoglycoside antibiotics.
Papaioannidou
P G
PG
Department of Pharmacology, Medical Faculty, Aristotelian University of Thessaloniki, Greece.
Karakiulakis
G
G
Triantaphyllidis
C
C
Paradelis
A G
AG
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D005839:Gentamicins / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D014649:Vas Deferens / Q000187:drug effects
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D002118:Calcium