Lange A B, Cheung I L
Department of Biology, Erindale College, University of Toronto at Mississauga, Ontario, Canada.
Peptides. 1999 Dec;20(12):1411-8. doi: 10.1016/s0196-9781(99)00150-3.
The external ventral protractor muscle of the VIIth abdominal segment, M234, is a skeletal muscle that possesses receptors that recognize a range of FMRFamide-related peptides and application of these peptides results in an increase in the amplitude of neurally evoked contractions with little or no effect on basal tonus. FLRFamide itself has the same biologic activity as the extended peptides, whereas truncation to LRFamide or RFamide results in a peptide with no biologic activity. The receptors recognizing these extended FLRFamides, which include SchistoFLRFamide, seem to be different from the SchistoFLRFamide receptors found on locust oviduct visceral muscle. SchistoFLRFamide and the non-peptide mimetic, benzethonium chloride (Bztc), increase the frequency and amplitude of miniature endplate potentials, increase the amplitude of neurally evoked excitatory junction potentials, and result in a hyperpolarisation of resting membrane potential. Bztc, however, also abolishes the active membrane response that may explain its ability to decrease neurally evoked contractions.
第七腹节的外部腹侧牵引肌，即M234，是一种骨骼肌，它拥有能够识别一系列FMRF酰胺相关肽的受体，应用这些肽会导致神经诱发收缩的幅度增加，而对基础张力几乎没有影响或没有影响。FLRF酰胺本身具有与延伸肽相同的生物活性，而截短为LRF酰胺或RF酰胺会产生没有生物活性的肽。识别这些延伸的FLRF酰胺（包括血吸虫FLRF酰胺）的受体似乎与在蝗虫输卵管内脏肌上发现的血吸虫FLRF酰胺受体不同。血吸虫FLRF酰胺和非肽模拟物苄索氯铵（Bztc）会增加微小终板电位的频率和幅度，增加神经诱发的兴奋性接头电位的幅度，并导致静息膜电位超极化。然而，Bztc也会消除可能解释其降低神经诱发收缩能力的主动膜反应。
