Harris W A, Cole J
J Neurogenet. 1984 Apr;1(2):127-40. doi: 10.3109/01677068409107078.
Embryonic eye primordia were transplanted from the anuran, Xenopus laevis, to the urodele, Ambystoma mexicanum, in order to assess whether retinal axons of one species could grow to appropriate central targets in a distantly related species. To trace the early retinal projections, Xenopus primordia were removed, incubated for 20 min in a solution containing [3H]proline, washed, and then transplanted to host axolotl embryos. Genetically eyeless hosts were used in some of the experiments so that the Xenopus optic fibers would not be guided to their targets by the host's own optic nerve projections. Xenopus eyes were usually able to differentiate into small eyes in the axolotl host. Shortly after primary differentiation, the development of these eyes seemed to arrest. Autoradiography on paraffin sections of the central nervous system of the host revealed that in some cases Xenopus retinal ganglion cells were indeed able to send axons to the tectum of the axolotl host. This result suggests that the mechanisms of axonal navigation for this particular central projection are evolutionarily conserved.
将无尾两栖类动物非洲爪蟾的胚胎眼原基移植到有尾两栖类动物墨西哥钝口螈体内，以评估一个物种的视网膜轴突是否能够生长到远亲物种的合适中枢靶点。为了追踪早期视网膜投射，取出非洲爪蟾原基，在含有[3H]脯氨酸的溶液中孵育20分钟，冲洗后移植到受体美西螈胚胎中。部分实验使用了基因无眼的受体，以便非洲爪蟾的视神经纤维不会被受体自身的视神经投射引导至其靶点。非洲爪蟾的眼睛通常能够在美西螈受体中分化为小眼睛。初次分化后不久，这些眼睛的发育似乎停滞。对受体中枢神经系统石蜡切片进行放射自显影显示，在某些情况下，非洲爪蟾视网膜神经节细胞确实能够将轴突发送至美西螈受体的顶盖。这一结果表明，这种特定中枢投射的轴突导航机制在进化上是保守的。
