神経筋接合部とA型ボツリヌス毒素製剤

The Neuromuscular Junction and Botulinum Toxin Type A

はじめに

　近年，A型ボツリヌス毒素製剤（以下BTX-A）が上肢・下肢痙縮の治療に用いられるようになり，その薬理作用が特異的に筋肉内の神経筋接合部^＊2（neuromuscular junction：NMJ）にあるために，その存在部位を認識しながらBTX-Aを筋肉内に注入することが肝心である．

Abstract : Injecting botulinum toxin type A (BTX-A) into spastic muscles is a recent alternative for treating conditions such as stroke, spinal cord injury, and cerebral palsy. BTX-A injection blocks acetylcholine release at the neuromuscular junction (NMJ) in the muscles. Therefore, BTX-A must be injected near the NMJ. In this paper, the anatomical, histochemical, and electrophysiological studies to determine the location of NMJs in the extremities are reviewed. Further, methylene blue vital staining as a method to identify the intramuscular nerve fibers and NMJs in the muscle and propose a so-called “mid portion of muscle fibers” along with the NMJ map of the upper and lower limbs are discussed.