Dolezal V, Vyskocil F, Tucek S
Pflugers Arch. 1983 Jun 1;397(4):319-22. doi: 10.1007/BF00580268.
Botulinum type A toxin (BoTx) has been found to diminish by 40% the spontaneous release of acetylcholine (ACh) from normal (acutely denervated) rat diaphragms incubated in the presence of 5 mM K+, while the release of ACh from chronically (4 days) denervated diaphragms was not affected during 2 h incubations. The toxin has been found to rapidly remove (within 10 min) the local depolarization of about 8 mV which developed in the end-plate zones of the diaphragms after the inhibition of cholinesterases; after the administration of BoTx, tubocurarine lost its ability to increase the resting membrane potential (H-response, Katz and Miledi 1977) in the end-plate area of anticholinesterase-treated muscles. It is concluded that BoTx inhibits the non-quantal release of ACh from the motor nerve fibres and that it probably acts directly on the nerve terminal surface membrane (without internalization). The H-response in the rat diaphragm reflects the non-quantal release of ACh from the nerve terminals and not from the muscle fibres.
已发现A型肉毒杆菌毒素（BoTx）可使在5 mM K⁺存在下孵育的正常（急性去神经支配的）大鼠膈肌中乙酰胆碱（ACh）的自发释放减少40%，而在慢性（4天）去神经支配的膈肌中，ACh的释放在2小时孵育期间未受影响。已发现该毒素能迅速（在10分钟内）消除在抑制胆碱酯酶后膈肌终板区出现的约8 mV的局部去极化；在施用BoTx后，筒箭毒碱失去了增加抗胆碱酯酶处理肌肉终板区静息膜电位（H反应，Katz和Miledi，1977）的能力。得出的结论是，BoTx抑制运动神经纤维中ACh的非量子释放，并且它可能直接作用于神经末梢表面膜（不发生内化）。大鼠膈肌中的H反应反映了神经末梢而非肌肉纤维中ACh的非量子释放。
