新しい局所麻酔薬, dl-cis-1-Benzoyloxy-2-dimethylamino-1,2,3,4-tetrahydronaphthalene(YAU-17)の神経筋伝達に対する作用

Abstract

YAU-17, a new local anesthetic, blocked the neuromuscular transmission in isolated frog sartorius muscle at a dose of 3×10-5M which prevented neither the directly elicited twitch of the muscle nor the conduction of action potential in isolated frog sciatic nerve trunk, indicating the site of action to be the neuromuscular junction. The blockade produced by YAU-17 was antagonized by guanidine, without being affected by neostigmine and potassium ion in the sartorius muscle preparations. Thus, the properties of YAU-17 in blocking neuromuscular transmission were similar to those of procaine and lidocaine, but not to those of d-tubocurarine whose neuromuscular blockade was antagonized by neostigmine and potassium ion. All of the drugs tested (YAU-17, procaine, lidocaine, and d-tubocurarine) inhibited the acetylcholine-induced contracture in the isolated frog rectus abdominis muscle. Although YAU-17, procaine, and lidocaine caused neuromuscular blockade in isolated frog sartorius muscle, these drugs in doses up to 30 mg/kg, i.v., given to rats anesthetized with pentobarbital had practically no effect on indirectly elicited contraction of gastrocnemius muscle. This held also true for cocaine and dibucaine, whereas d-tubocurarine consistently exhibited muscle relaxing action in both preparations. These results indicate that the effects of YAU-17 on neuromuscular transmission were similar to those of local anesthetics, procaine and lidocaine, but not to those of d-tubocurarine.