河豚毒素对金鱼再生的视网膜顶盖投射模式的影响

THE EFFECT OF TTX ACTIVITY BLOCKADE ON THE REFINEMENT OF REGENERATED RETINOTECTAL PROJECTION IN GOLDFISH

本文用微量注射荧光染料ＤｉＩ顺标记的方法，研究了河豚毒素（ＴＴＸ）阻断神经传人活动对金鱼再生的视网膜顶盖投射模式的影响，结果表明：ＴＴＸ处理后再生的视网膜顶盖投射，象正常再生过程一样，经历了修整的过程，包括再生到顶盖错误区域的视神经纤维的消失和在再生的视神经纤维主干上生长的侧支的消失，与正常再生过程不同的是，再生晚期到达顶盖靶区的视神经纤维的终末分支不再相互重叠，而是彼此分离，另外，终末分支的分支数和分支的末梢数均少于对照组，这提示，再生的视网膜顶盖投射的形成以及与功能相关的精细结构的重建依赖于视神经的传入活动。

The effect of TTX impulse blockade on the refinement of regenerated retinotectal projection in goldfish was studied with microinjection of fluorescent dye DiⅠ labeling antrogradely. The results show that the refinement of regenerated retinotectal projection treated with TTX underwent similar courses as in the control, including disappearance of the optic fibers, distributed in inappropriate tectal areas and of the side branchs on the shafts of the optic fibers. But the relative positions and the morphology of the terminal arbors of TTX-blocked fibers were different from the control. In TTX-group the terminal arbors of the optic fibers arrived at tectal target were separated from each other, did not overlapped as in normal regeneration, and the branches and branch endings of the arbors were less in TTX-group than that in the control. These results suggest that the refinement of regenerated retinotectal projection and reestablishment of fine morphological structure correlated to visual function are dependent on the impulse activity.