Seasonal plasticity in the copulatory neuromuscular system of green anole lizards: a role for testosterone in muscle but not motoneuron morphology.
Seasonal plasticity in the copulatory neuromuscular system of green anole lizards: a role for testosterone in muscle but not motoneuron morphology.
复制标题
绿变色龙交配神经肌肉系统的季节性可塑性：睾酮在肌肉而非运动神经元形态中的作用。
DOI：
10.1002/neu.10334
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Wade,Juli
中科院分区：
文献类型：
--
作者：
Holmes,MelissaM;Wade,Juli
The copulatory system of green anoles is highly sexually dimorphic. Males possess bilateral copulatory organs called hemipenes, each independently controlled by two muscles: the transversus penis (TPN) and retractor penis magnus (RPM). The TPN everts the hemipene through the cloaca and the RPM retracts it. Adult females do not possess hemipenes or either of these two muscles. The spinal nucleus projecting to the TPN and RPM contains more and larger motoneurons in males than females. Because anoles breed seasonally, two experiments were designed to test whether adult copulatory morphology varies with environmental condition, and if so, whether the effect is mediated by testicular androgens. Three groups of adult males were used in each experiment: males from breeding environmental conditions with reproductive testes (BS); males in breeding conditions with regressed testes (BS‐X); and males in nonbreeding conditions with regressed testes (NBS). Experiment 1 compared gonadally intact males and Experiment 2 compared castrated males treated with either testosterone (T) or an empty implant. In both experiments, copulatory and control motoneurons appeared smaller in NBS males, but T did not affect their size. In contrast, while hemipene and RPM muscle fiber size were not plastic across season in gonadally intact males, T in castrated males significantly increased both measures under BS and BS‐X, but not NBS, conditions. These results demonstrate that neuron soma size might change on a general level and environmental cues can mediate T‐induced changes in peripheral structures, suggesting that plasticity across copulatory system components is regulated by different mechanisms. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 1–11, 2004
