Hypophysectomy and the Tail Darkening Reaction in Xenopus. ∗
Hypophysectomy and the Tail Darkening Reaction in Xenopus. ∗
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爪蟾的垂体切除术和尾部变黑反应。
DOI：
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发表时间：
1957
期刊：
影响因子：
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通讯作者：
J. T. Bagnara
中科院分区：
文献类型：
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作者：
J. T. Bagnara
人们早就知道，如果从两栖类胚胎中移除脑垂体胎盘，产生的幼虫将非常苍白，不同物种的幼虫颜色不同，从白色或银色，到金黄色(1，2)。面色苍白通常是由于表皮黑素载体的持续收缩和真皮和表皮团的扩张所致(2)。因此，令人惊讶的是，观察到在垂体鲨幼虫中，在适当的条件下，尾部的黑色素能够相当大地扩张或收缩。本文报道的实验旨在研究脑垂体对非洲爪哇幼虫某些着色团行为的影响，并对尾部黑色素团的特殊活动有一定的了解。方法：研究方法。所有的蝌蚪都是用非洲爪哇的自然产卵饲养的。在尾芽早期，从378个胚胎中去除了垂体部胎盘。从所产生的苍白幼虫的数量来看，大约85%的手术动物完成了脑垂体切除。这些幼虫中只有25%在2周后存活下来，因为它们的口腔部位受到了严重的损害。对同一批卵的正常幼虫和垂体性腹鳍幼虫的腹鳍进行了黑素细胞计数。从尾部着色区前缘到鳍和体节中间约三分之一的区域被选为计数区域。用目测微尺对每组6只幼虫进行测量。在放大45倍的情况下，将封闭在一个正方形中的黑素细胞计数为25个正方形，然后计算出每只蝌蚪的平均每平方数。
It has long been known that if the hypophyseal placode is removed from amphibian embryos, the resulting larvae will be very pale in appearance and vary in color in different species from white or silver, to golden yellow (1,2). Pallor generally results from persistent contraction of epidermal melanophores and expansion of both dermal and epidermal guanophores (2). It is therefore surprising to observe that in hypophysioprivic Xenopus larvae, melanophores of the tail are capable of considerable expansion or contraction under appropriate conditions. The experiments reported here were designed to study the influence of the hypophysis on the behavior of some of the chromatophores of Xenopus larvae, and to gain some insight into the peculiar activity of melanophores in the tail. Methods. All tadpoles were raised from naturally spawned eggs of Xenopus laevis Daudin. At an early tailbud stage, the hypophyseal placode was removed from 378 embryos. Judging from the number of pale larvae resulting, removal of the hypophysis was accomplished in about 85% of the operated animals. Only about 25% of these larvae survived after 2 weeks, because of severe damage to their mouth parts. Melanophore counts were made in the ventral fin of both normal and hypophysioprivic larvae of the same egg batch. An area about one-third the distance from the anterior margin of the pigmented region of the tail and midway between fin and somites was selected for the counts. These were made using an ocular micrometer on 6 larvae from each group. Under magnification of 45X, melanophores enclosed in a square, one-sixteenth of a square cm in size, were counted for 25 squares and the average number per square was then determined for each tadpole.