The neuromuscular blocking effect of dibekacin and its reversal by Ca2+ and drugs in the isolated rat phrenic-hemidiaphragm preparation.
1. Dibekacin (0.3-3 mM) reduced indirectly elicited twitches in rat phrenic-hemidiaphragm. This effect was potentiated in low extracellular calcium media. 2. The blockade induced by dibekacin (3 mM) could be reversed by calcium (2.5 mM), 3,4-diamino-pyridine (3,4-DAP, 10 microM) or guanidine (3 mM), whereas neostigmine (3 microM), eserine (25 microM) or tetraethylammonium (100 microM) were less potent. 3. Dibekacin (3 mM) blocked directly-elicited twitches. Low concentrations were unable to obtain any effect. 4. It is concluded that dibekacin exerts its blocking action by limiting the calcium entry at motor nerve terminals, but a postsynaptic effect is also present. 3,4-DAP, guanidine and calcium were the most potent drugs in reversing the blockade.
Baños
J E
JE
Departament de Farmacologia i Psiquiatria, Facultat de Medicina, Universitat Autonoma de Barcelona, Bellaterra, Spain.
Bosch
F
F
Badia
A
A
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D003964:Diaphragm / Q000187:drug effects / Q000294:innervation; D003982:Dibekacin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D007612:Kanamycin / Q000031:analogs & derivatives*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009466:Neuromuscular Blocking Agents; D009469:Neuromuscular Junction / Q000187:drug effects; D010791:Phrenic Nerve / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012132:Respiratory Muscles / Q000187:drug effects* / Q000294:innervation
D009466:Neuromuscular Blocking Agents; D003982:Dibekacin; D007612:Kanamycin; D002118:Calcium