Protti D A, Uchitel O D
Institute of Cell Biology, Faculty of Medicine, University of Buenos Aires, Argentina.
Neuroreport. 1993 Dec 13;5(3):333-6. doi: 10.1097/00001756-199312000-00039.
Mammalian neuromuscular transmission is resistant to L and N type calcium channel blockers but very sensitive to a low molecular weight funnel web spider venom toxin, FTX, which selectively blocks P type calcium channels. To further characterize the calcium channels involved in neuromuscular transmission we studied the effect of omega Agatoxin (omega-Aga-IVA) a polypeptide P type channel blocker from the same spider venom. We show that omega-Aga-IVA is a potent and irreversible inhibitor of the presynaptic Ca2+ currents and of acetylcholine release induced by electrical stimulation or by K+ depolarization. This provides further evidences that transmitter release at the mammalian neuromuscular junction is mediated by P type Ca2+ channels.
哺乳动物的神经肌肉传递对L型和N型钙通道阻滞剂具有抗性，但对一种低分子量漏斗网蜘蛛毒液毒素FTX非常敏感，FTX可选择性阻断P型钙通道。为了进一步表征参与神经肌肉传递的钙通道，我们研究了来自同一种蜘蛛毒液的多肽P型通道阻滞剂ω-阿加毒素（ω-Aga-IVA）的作用。我们发现ω-Aga-IVA是突触前Ca2+电流以及电刺激或K+去极化诱导的乙酰胆碱释放的强效且不可逆的抑制剂。这进一步证明，哺乳动物神经肌肉接头处的递质释放是由P型Ca2+通道介导的。
