Wang Z, Orchard I, Lange A B, Chen X
Department of Zoology, University of Toronto, Ontario, Canada.
Neuropeptides. 1995 Mar;28(3):147-55. doi: 10.1016/0143-4179(95)90109-4.
The possible mode of action of an inhibitory neuropeptide SchistoFLRFamide (PDVDHVFLRFamide) on locust oviduct visceral muscle was studied by examining its ability to inhibit calcium ionophore A23187-, caffeine- or phorbol ester-induced oviduct contractions. A23187-induced muscle contractions included two components: one which required the influx of extracellular Ca2+ through Ca2+ channels (blocked by cobalt ions), the other not blocked by cobalt ions. SchistoFLRFamide inhibited the cobalt-sensitive components, but not the latter. Caffeine induced two phases of contractions, a phasic contraction which was probably due to the release of intracellular Ca2+ and a tonic contraction which required the influx of extracellular Ca2+. SchistoFLRFamide inhibited the tonic contraction in a dose-dependent manner but did not influence the phasic contraction. The phorbol 12-myristate 13-acetate-induced muscle contraction required the presence of extracellular Ca2+, with Ca2+ probably entering through ligand-gated channels, but the contraction was not inhibited by SchistoFLRFamide. Based upon these results, it appears that SchistoFLRFamide inhibits muscle contraction by preventing the accumulation of free intracellular Ca2+ from extracellular stores. SchistoFLRFamide is incapable of inhibiting contraction induced by the release of intracellular stores of Ca2+. It is possible that SchistoFLRFamide closes or blocks voltage-gated and some ligand-gated Ca2+ channels in the plasma membrane.
通过检测抑制性神经肽血吸虫FLRF酰胺（PDVDHVFLRF酰胺）抑制钙离子载体A23187、咖啡因或佛波酯诱导的蝗虫输卵管内脏肌收缩的能力，研究了其可能的作用方式。A23187诱导的肌肉收缩包括两个成分：一个成分需要细胞外Ca2+通过Ca2+通道内流（被钴离子阻断），另一个成分不被钴离子阻断。血吸虫FLRF酰胺抑制钴敏感成分，但不抑制后者。咖啡因诱导两个收缩阶段，一个可能由于细胞内Ca2+释放引起的相性收缩和一个需要细胞外Ca2+内流的强直性收缩。血吸虫FLRF酰胺以剂量依赖方式抑制强直性收缩，但不影响相性收缩。佛波醇12-肉豆蔻酸酯13-乙酸酯诱导的肌肉收缩需要细胞外Ca2+的存在，Ca2+可能通过配体门控通道进入，但该收缩不被血吸虫FLRF酰胺抑制。基于这些结果，似乎血吸虫FLRF酰胺通过阻止细胞内游离Ca2+从细胞外储存库积累来抑制肌肉收缩。血吸虫FLRF酰胺不能抑制由细胞内Ca2+储存库释放诱导的收缩。血吸虫FLRF酰胺可能会关闭或阻断质膜中的电压门控和一些配体门控Ca2+通道。
