Vocal pathway degradation in gonadectomized Xenopus laevis adults.
Vocal pathway degradation in gonadectomized Xenopus laevis adults.
复制标题
性腺切除的非洲爪蟾成虫的声音通路退化。
DOI：
10.1152/jn.00883.2010
复制
发表时间：
2011
影响因子：
2.5
通讯作者：
Yamaguchi,Ayako
中科院分区：
文献类型：
--
作者：
Zornik,Erik;Yamaguchi,Ayako
许多脊椎动物的生殖行为在成年雄性体内通过雄激素水平升高而激活，并通过阉割而终止。控制这些行为的神经和肌肉成分包含许多激素敏感部位，包括运动起始中心（如基底神经节）、中枢模式发生器（CPGs）和肌肉；因此，很难单独使用行为分析来确认每种激素激活靶标的作用。我们的目标是通过确定雄激素诱导的声音激活的位置来解决这个问题，使用雄狐猴laevis，一种之前已经确定声音激活的雄激素依赖性的物种。我们比较了去势雄性和对照雄性的两种体外制备——分离的喉部和分离的大脑——在体内的鸣叫模式和功能。孤立的喉部使我们能够测试被阉割的雄性是否有能力将雄性典型的神经信号转化为发声，而有效发声的大脑准备使我们能够直接检查声音CPG功能，而不是声音启动的问题。结果表明，所有三个组成部分——发声起始、CPG和喉部——都需要完整的性腺。去势雄鼠的声带功能显著下降，喉部收缩特性被阉割，而对照组动物没有观察到变化。此外，与对照组相比，阉割鼠的有效叫声有所降低。据我们所知，这一发现首次证明了性腺依赖性CPG对成年期求爱行为的维持。由于先前的研究表明雄激素替代可以预防阉割引起的声带损伤，我们得出结论，声带起始中心、喉部和CPG功能的退化最有可能是由于类固醇激素的剥夺。
Reproductive behaviors of many vertebrate species are activated in adult males by elevated androgen levels and abolished by castration. Neural and muscular components controlling these behaviors contain numerous hormone-sensitive sites including motor initiation centers (such as the basal ganglia), central pattern generators (CPGs), and muscles; therefore it is difficult to confirm the role of each hormone-activated target using behavioral assays alone. Our goal was to address this issue by determining the site of androgen-induced vocal activation using maleXenopus laevis, a species in which androgen dependence of vocal activation has been previously determined. We compared in vivo calling patterns and functionality of two in vitro preparations—the isolated larynx and an isolated brain from which fictive courtship vocalizations can be evoked—in castrated and control males. The isolated larynx allowed us to test whether castrated males were capable of transducing male-typical nerve signals into vocalizations and the fictively vocalizing brain preparation allowed us to directly examine vocal CPG function separate from the issue of vocal initiation. The results indicate that all three components—vocal initiation, CPG, and larynx—require intact gonads. Vocal production decreased dramatically in castrates and laryngeal contractile properties of castrated males were demasculinized, whereas no changes were observed in control animals. In addition, fictive calls of castrates were degraded compared with those of controls. To our knowledge, this finding represents the first demonstration of gonad-dependent maintenance of a CPG for courtship behavior in adulthood. Because previous studies showed that androgen-replacement can prevent castration-induced vocal impairments, we conclude that degradation of vocal initiation centers, larynx, and CPG function are most likely due to steroid hormone deprivation.