Neuromuscular Blocking Properties of Various Polypeptide Antibiotics.

Abstract

Colistin sulfate, neomycin sulfate, polymyxin A sulfate, polymyxin B sulfate, and viomycin sulfate produced neuromuscular blockade when tested on sciatic nerve-gastrocnemius muscle preparations of the rabbit. Data obtained from the neuromuscular preparations were statistically analyzed and the relative potencies of the antibiotics in relation to colistin sulfate were determined. Polymyxin B sulfate was the most active antibiotic, approximately 1.5 times as active as colistin sulfate. Neostigmine methylsulfate antagonized the neuromuscular blockade produced by neomycin sulfate and viomycin sulfate, but was not an effective antagonist of the blockade produced by colistin sulfate, polymyxin A sulfate, and polymyxin B sulfate. Colistin sulfate, polymyxin A sulfate and polymyxin B sulfate do not produce contracture when administered to the chicken. The amino acids and other constituents comprising the various peptide antibiotics failed to show neuromuscular blocking activity.