Foldes F F, Bikhazi G B
Department of Anesthesiology, University of Miami School of Medicine, Florida 33101.
Acta Physiol Pharmacol Latinoam. 1989;39(4):343-52.
To obtain information on the sites and mechanisms of the myoneural effect of aminoglycoside and polypeptide type antibiotics, the influence of neomycin, streptomycin, gentamicin and polymyxin B on the depression of the force of contraction (P) of the rat phrenic nerve-hemidiaphragm preparation was investigated at 37 degrees C, 27 degrees C or 17 degrees C and also at 37 degrees C in electrolyte solutions containing 2.5, 1.25 or 0.625 mM CaCl2. Decreasing the temperature or the CaCl2 concentration ((CaCl2)o) of the bath significantly (p less than 0.001) decreased P. The depressant effect of aminoglycosides on P (about 50% of control at 17 degrees C) was increased more with lower temperatures than that of polymyxin B (about 20%). The effect of lowering the (CaCl2)o on the depression of P (about 90% of control at the lowest (CaCl2)o) was about the same with the 4 antibiotics. The development of the maximal effect and the recovery of P after washout was slower with polymyxin B than with the 3 aminoglycosides. 4-Aminopyridine antagonized the depression of P caused by polymyxin B less than that caused by aminoglycosides. The findings suggest that aminoglycosides depress myoneural activity primarily by inhibiting stimulated release of ACh. Polymyxin B also inhibits ACh release, but inhibition of the contraction of myofibrils contributes more significantly to its myoneural effects than with aminoglycosides. It is conceivable that blocking of the ionophores of the postjunctional membrane also contributes to the myoneural effects of polymyxin B.
为获取关于氨基糖苷类和多肽类抗生素肌神经效应的部位及机制的信息，研究了新霉素、链霉素、庆大霉素和多粘菌素B在37℃、27℃或17℃以及在含有2.5、1.25或0.625 mM氯化钙的电解质溶液中于37℃时对大鼠膈神经 - 半膈肌标本收缩力（P）抑制的影响。降低浴温或氯化钙浓度（(CaCl₂)ₒ）会显著（p < 0.001）降低P。氨基糖苷类对P的抑制作用（在17℃时约为对照的50%）随温度降低的增加幅度大于多粘菌素B（约20%）。降低(CaCl₂)ₒ对P抑制的作用（在最低(CaCl₂)ₒ时约为对照的90%）在这4种抗生素中大致相同。多粘菌素B作用后最大效应的产生及冲洗后P的恢复比3种氨基糖苷类更慢。4 - 氨基吡啶对多粘菌素B引起的P抑制的拮抗作用小于对氨基糖苷类引起的P抑制的拮抗作用。这些发现表明，氨基糖苷类主要通过抑制乙酰胆碱的刺激释放来降低肌神经活性。多粘菌素B也抑制乙酰胆碱释放，但与氨基糖苷类相比，其对肌原纤维收缩的抑制对其肌神经效应的贡献更为显著。可以设想，阻断接头后膜的离子载体也对多粘菌素B的肌神经效应有贡献。
