Endo M, Iino M
J Muscle Res Cell Motil. 1980 Mar;1(1):89-100. doi: 10.1007/BF00711927.
The effects of saponin on Xenopus and frog skeletal muscle fibres were examined. The twitch of Xenopus single fibres was first potentiated slightly and then irreversibly abolished by 5-10 microgram/ml of saponin. Treatment with saponin at 5-10 microgram/ml or higher concentrations for 30 min resulted in perforation of the muscle cell membrane, indicated by the following evidence. (i) Fibres became responsive to contractile activating solutions with a pCa-tension relationship similar to that of mechanically skinned fibres. (ii) Removal and re-introduction of MgATP became effective in bringing fibres into rigor and the relaxed state, respectively. (iii) After the saponin treatment large contractions due to Ca release from the SR could be elicited by substitution of Cl for methanesulphonate in the medium. (iv) The treatment decreased the optical path length across the fibre, indicating loss of soluble proteins. (v) The lattice spacing of myofilaments was wider after the treatment as in mechanically skinned fibres. Contractile response of mechanically skinned fibres and their SR responses such as Ca uptake, Ca-induced Ca release and Cl-induced Ca release were not affected by treatment with 50 microgram/ml saponin for 30 min, while 150 microgram/ml or higher concentrations severely impaired by the SR functions. It is possible, therefore, to make chemically skinned skeletal muscle fibres in which the functions of the SR are preserved by applying 10-50 microgram/ml saponin.
研究了皂苷对非洲爪蟾和青蛙骨骼肌纤维的影响。5 - 10微克/毫升的皂苷首先会使非洲爪蟾单纤维的抽搐稍有增强，随后不可逆地消除。用5 - 10微克/毫升或更高浓度的皂苷处理30分钟会导致肌肉细胞膜穿孔，证据如下：(i)纤维对收缩激活溶液有反应，其pCa - 张力关系与机械去皮纤维相似。(ii)去除并重新加入MgATP分别能有效地使纤维进入强直状态和松弛状态。(iii)皂苷处理后，通过在培养基中用Cl替代甲磺酸盐可引发因肌浆网释放Ca而产生的大收缩。(iv)处理后纤维的光程长度减小，表明可溶性蛋白质流失。(v)处理后肌丝的晶格间距变宽，与机械去皮纤维的情况相同。机械去皮纤维的收缩反应及其肌浆网反应，如Ca摄取、Ca诱导的Ca释放和Cl诱导的Ca释放，不受50微克/毫升皂苷处理30分钟的影响，而150微克/毫升或更高浓度则会严重损害肌浆网功能。因此，通过应用10 - 50微克/毫升的皂苷，可以制备出保留肌浆网功能的化学去皮骨骼肌纤维。
