Lee C Y, Tsai M C, Tsaur M L, Lin W W, Carlsson F H, Joubert F J
J Pharmacol Exp Ther. 1985 May;233(2):491-8.
Five angusticeps-type toxins, F7, F8 and C10S2C2 from Dendroaspis angusticeps and C and FS2 from D. polylepis polylepis, were tested for action on the chick biventer cervicis nerve-muscle, the frog rectus abdominis muscle and the mouse phrenic nerve-diaphragm preparations. In the chick muscle, none of these toxins exhibited any stimulatory effect up to 100 micrograms/ml. In the frog muscle, the response to acetylcholine, but not to carbachol, was enhanced dose dependently by F7 and C. No appreciable effect was observed with the other three toxins. In the mouse diaphragm, also only F7 and C augmented responses to indirect stimulation and produced spontaneous fasciculations. On tetanic stimulation, a marked Wedensky inhibition was observed. Their stimulatory effect was abolished by d-tubocurarine. In the presence of d-tubocurarine as well as in the denervated mouse diaphragm, neither toxin increased responses to direct stimulation. In low-calcium (0.6 mM) or high magnesium (4.2 mM) medium, the stimulatory effect of both toxins was markedly attenuated. The resting membrane potential of the mouse diaphragm was not changed. The amplitude and frequency of MEPPs and the quantal content and the half-decay time of EPPs was increased. Both toxins also produced a stimulatory effect on the isolated guinea-pig ileum, which was abolished by atropine. In the rat atrial preparation, both toxins caused negative inotropic and chronotropic effects, which were reversed by atropine. If pretreated with atropine, these effects were completely prevented. Both F7 and C markedly inhibited the cholinesterase activity of the homogenized mouse diaphragm and frog rectus abdominis muscle but not that of the chick biventer cervicis muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
对来自绿曼巴蛇（Dendroaspis angusticeps）的5种绿曼巴蛇型毒素（F7、F8和C10S2C2）以及来自多鳞绿曼巴蛇（D. polylepis polylepis）的C和FS2进行了测试，观察它们对鸡颈二腹肌神经 - 肌肉、青蛙腹直肌以及小鼠膈神经 - 膈肌标本的作用。在鸡肌肉中，这些毒素在浓度高达100微克/毫升时均未表现出任何刺激作用。在青蛙肌肉中，F7和C剂量依赖性地增强了对乙酰胆碱而非卡巴胆碱的反应。其他三种毒素未观察到明显作用。在小鼠膈肌中，同样只有F7和C增强了对间接刺激的反应并产生自发束颤。强直刺激时，观察到明显的韦登斯基抑制。它们的刺激作用被筒箭毒碱消除。在存在筒箭毒碱的情况下以及在去神经支配的小鼠膈肌中，两种毒素均未增加对直接刺激的反应。在低钙（0.6毫摩尔）或高镁（4.2毫摩尔）培养基中，两种毒素的刺激作用均明显减弱。小鼠膈肌的静息膜电位未改变。微小终板电位的幅度和频率、终板电位的量子含量以及半衰减时间均增加。两种毒素对离体豚鼠回肠也产生刺激作用，该作用被阿托品消除。在大鼠心房标本中，两种毒素均引起负性变力和变时作用，阿托品可使其逆转。若预先用阿托品处理，则可完全防止这些作用。F7和C均显著抑制匀浆后的小鼠膈肌和青蛙腹直肌的胆碱酯酶活性，但不抑制鸡颈二腹肌的胆碱酯酶活性。（摘要截选至250字）
