Deshpande S S, Sheridan R E, Adler M
Neurotoxicology Branch, USAMRICD, Aberdeen Proving Ground, MD 21010-5425, USA.
Toxicon. 1995 Apr;33(4):551-7. doi: 10.1016/0041-0101(94)00188-e.
Zinc-dependent metalloprotease inhibitors phosphoramidon, captopril and a peptide hydroxamate were studied as potential pretreatment compounds by examining their ability to delay the onset or to prolong the time to 50% block of nerve-elicited muscle twitch tension in the mouse phrenic-nerve diaphragm (in vitro at 36 degrees C) after botulinum neurotoxin serotypes A and B (BoNT-A, BoNT-B). Addition of BoNT-A or BoNT-B (1 x 10(-10) M) produced 50% block of the twitch response at 56 +/- 9 min and 76 +/- 4 min, respectively. Preincubation (45 min) of muscles with phosphoramidon (0.2 mM) prolonged the time to 50% block by 15 min in BoNT-B-poisoned muscles with no effect on the time-course of paralysis in BoNT-A exposed muscles. When the same quantities of BoNT-A or BoNT-B (equivalent to 1 x 10(-10) M bath concentration) were preincubated for 2 hr with phosphoramidon (equivalent to 0.2 mM final bath concentration), and the incubation mixture was added to the muscle chamber, the times to 50% block were prolonged by 38 min and 18 min for BoNT-B and BoNT-A, respectively. Preincubation of diaphragms with captopril (up to 10 mM) or peptide hydroxamate (75 microM) failed to antagonize BoNT-A or BoNT-B-induced neuromuscular block. Among the three metalloprotease inhibitors examined here, only phosphoramidon showed a significant protection against both serotypes of BoNT. A search for better inhibitor compounds specifically tailored to match the active site on BoNT molecule deserves attention.
通过检测锌依赖性金属蛋白酶抑制剂磷酰胺素、卡托普利和一种肽羟基肟酸酯延迟肉毒杆菌神经毒素A和B（BoNT-A、BoNT-B）中毒后小鼠膈神经膈肌（36℃体外）神经诱发肌肉抽搐张力50%阻滞的起始时间或延长其达到该阻滞时间的能力，对它们作为潜在预处理化合物进行了研究。添加BoNT-A或BoNT-B（1×10⁻¹⁰ M）分别在56±9分钟和76±4分钟时使抽搐反应产生50%阻滞。用磷酰胺素（0.2 mM）对肌肉进行预孵育（45分钟），可使BoNT-B中毒肌肉达到50%阻滞的时间延长15分钟，而对BoNT-A中毒肌肉的麻痹时间进程无影响。当相同量的BoNT-A或BoNT-B（相当于浴液浓度1×10⁻¹⁰ M）与磷酰胺素（相当于最终浴液浓度0.2 mM）预孵育2小时，然后将孵育混合物加入肌肉腔室时，BoNT-B和BoNT-A达到50%阻滞的时间分别延长38分钟和18分钟。用卡托普利（高达10 mM）或肽羟基肟酸酯（75 μM）对膈肌进行预孵育未能拮抗BoNT-A或BoNT-B诱导的神经肌肉阻滞。在此检测的三种金属蛋白酶抑制剂中，只有磷酰胺素对两种血清型的BoNT均显示出显著的保护作用。寻找更适合与BoNT分子活性位点匹配的更好的抑制剂化合物值得关注。
