Harris W A
J Comp Neurol. 1980 Nov 15;194(2):303-17. doi: 10.1002/cne.901940203.
The California newt Taricha torosa manufactures tetrodotoxin, a blocker of voltage-sensitive sodium channels and therefore of action potentials.The newt's own nervous system is insensitive to this toxin. Grafting an embryonic eye to the newt from a tetrodotoxin-sensitive species, the Mexican axolotl, blocks action potentials in the retinal ganglion cells of the transplanted eye. Neuroanatomical and electrophysical techniques demonstrate that while such ganglion cells are incapable of firing impulses, they develop normally, grow axons to the host tectum, terminate in the appropriate neuropil layers, form synapses, and project to the tectum retinotopically. Furthermore, they develop these apparently normal projections even in competition with electrically active axons from a host eye.
加州蝾螈（Taricha torosa）能制造河豚毒素，这种毒素是电压敏感性钠通道的阻滞剂，因而也是动作电位的阻滞剂。蝾螈自身的神经系统对这种毒素不敏感。将来自对河豚毒素敏感的物种——墨西哥钝口螈的胚胎眼睛移植到加州蝾螈身上，会阻断移植眼睛视网膜神经节细胞中的动作电位。神经解剖学和电生理学技术表明，虽然这类神经节细胞无法产生冲动，但它们发育正常，长出轴突至宿主视顶盖，在适当的神经毡层终止，形成突触，并以视网膜拓扑方式投射至视顶盖。此外，即使与来自宿主眼睛的电活动轴突竞争，它们仍能形成这些看似正常的投射。
