Mauss S, Koch G, Kreye V A, Aktories K
Rudolf-Buchheim-Institut für Pharmakologie, Universität Giessen, Federal Republic of Germany.
Naunyn Schmiedebergs Arch Pharmacol. 1989 Sep;340(3):345-51. doi: 10.1007/BF00168521.
The effect of botulinum C2 toxin was studied on the contractions of the guinea pig ileum myenteric plexus longitudinal muscle preparation. Botulinum C2 toxin inhibited the muscle contraction induced by electrical stimulation (60 V; 0.5 ms; 0.33 Hz) in a time and concentration dependent manner. The inhibitory effect occurred with a time lag of about 1 h, and depended on the presence of both toxin components. After 4 h of incubation with 1.7 micrograms/ml of component I and 6.7 micrograms/ml of component II of botulinum C2 toxin, the smooth muscle contraction was inhibited by about 60%. At these toxin concentrations, about 55% of the modifiable smooth muscle actin was ADP-ribosylated. Smooth muscle contraction induced by bradykinin and bethanechol were similarly inhibited. Moreover, the C2 toxin inhibited muscle contraction induced by Ba2+, and by direct muscle membrane depolarization (60 V; 10 ms; 0.33 Hz) after suppression of acetylcholine release by normorphine. Also cytochalasin D inhibited the electrically evoked contraction of the ileum longitudinal muscle. In contrast to botulinum C2 toxin, inhibition of contractility by cytochalasin D occurred without a lag phase, and was reversed by washing off the toxin. In contrast of guinea pig ileum longitudinal muscle, botulinum C2 toxin did not reduce the contraction of the rabbit aortic smooth muscle stimulated by K+-depolarization or noradrenaline.
研究了肉毒杆菌C2毒素对豚鼠回肠肌间神经丛纵肌标本收缩的影响。肉毒杆菌C2毒素以时间和浓度依赖的方式抑制电刺激（60V；0.5ms；0.33Hz）诱导的肌肉收缩。抑制作用出现约1小时的延迟，且依赖于两种毒素成分的存在。用1.7微克/毫升的肉毒杆菌C2毒素成分I和6.7微克/毫升的成分II孵育4小时后，平滑肌收缩被抑制约60%。在这些毒素浓度下，约55%的可修饰平滑肌肌动蛋白被ADP-核糖基化。缓激肽和氨甲酰甲胆碱诱导的平滑肌收缩也受到类似抑制。此外，C2毒素抑制Ba2+诱导的肌肉收缩，以及在去甲吗啡抑制乙酰胆碱释放后直接肌肉膜去极化（60V；10ms；0.33Hz）诱导的肌肉收缩。细胞松弛素D也抑制回肠纵肌的电诱发收缩。与肉毒杆菌C2毒素不同，细胞松弛素D对收缩性的抑制没有延迟期，且通过洗去毒素可逆转。与豚鼠回肠纵肌相反，肉毒杆菌C2毒素不降低K+去极化或去甲肾上腺素刺激的兔主动脉平滑肌的收缩。
