The effect of CO2-induced acid-base changes on the potencies of muscle relaxants and antagonism of neuromuscular block by neostigmine in rat in vitro

摘要: We investigated the influence of CO2-induced acid-base changes on potencies monoquaternary relaxants (rocuronium, vecuronium, and d-tubocurarine) bisquaternary (pancuronium, pipecuronium, metocurine), antagonism their neuromuscular block by neostigmine. Phrenic nerve-hemidiaphragm preparations rats were used. The pH induced changing CO2 concentration aerating modified Krebs solution. increased at 9% (pH 7.2) decreased 2.5% 7.6) from those 5% 7.4) both with without neostigmine (P < 0.05), whereas drugs did not change significantly different levels control slopes log concentration-percent response curves each drug level. ratios inhibitory concentrations, 50% (IC50) values value for indicating that neostigmine-induced was affected changes. But IC50 steroidal pancuronium, pipecuronium) lower 0.05) than isoquinolinium (d-tubocurarine metocurine) level, suggesting is enhanced level relaxants. difference independent or nature. These results suggest increases potency but does affect relaxants.(ABSTRACT TRUNCATED AT 250 WORDS)