Holman S D, Rice A
Department of Anatomy, University of Cambridge, United Kingdom.
Horm Behav. 1996 Dec;30(4):662-72. doi: 10.1006/hbeh.1996.0067.
The relationship between courtship ultrasound emission rates and the volume of a discrete, sex-related, hypothalamic nucleus, the sexually dimorphic area, pars compacta (SDApc), in male and neonatally androgenized female gerbils is lateralized. Unbiased stereological estimates of neuron number and nuclear and neuropil volume are also laterally asymmetric in male SDApcs. In this study sexual differentiation and lateral asymmetry of stereologically assessed cytoarchitectural SDApc components, and their relationship to male-typical behaviors, including vocal emission, were examined in masculinized females. Female neonates received a single injection of testosterone propionate (TP) or control vehicle (Control) and were then implanted with silastic cannulae of testosterone at 65 days of age. Total SDApc volume, neuron number, nuclear volume, and neuropil volume had significantly greater values in TP compared to Control females. Neuron number was laterally asymmetric in TP females, since the left SDApc contained a greater number of smaller neurons, possibly interneurons, than the right. Courtship vocal emission and two other behaviors were masculinized in TP females. Left SDApc total volume and, most significantly, left neuron number, were correlated with vocal rates. No other lateralized correlations between behaviors and stereological estimates were found. It was concluded that various stereological parameters and the lateralization of vocal behavior and brain asymmetry depend on the early sexually differentiating effects of androgens. It is suggested that in gerbils, androgens have a role in the survival of interneurons in a laterally asymmetric hypothalamic nucleus which is an index of vocal control.
在雄性和新生期经雄激素化的雌性沙鼠中，求偶超声发射率与一个离散的、与性别相关的下丘脑核团——性二态区致密部（SDApc）的体积之间的关系存在侧化现象。对雄性SDApc中神经元数量以及核体积和神经毡体积的无偏立体学估计也存在侧化不对称。在本研究中，对经雄性化处理的雌性沙鼠进行了立体学评估的细胞构筑学SDApc成分的性分化和侧化不对称研究，以及它们与包括发声在内的雄性典型行为之间的关系。雌性新生鼠接受单次丙酸睾酮（TP）注射或对照溶剂注射（对照），然后在65日龄时植入睾酮硅橡胶套管。与对照雌性相比，TP雌性的SDApc总体积、神经元数量、核体积和神经毡体积显著更大。TP雌性的神经元数量存在侧化不对称，因为左侧SDApc中比右侧含有更多数量的较小神经元，可能是中间神经元。TP雌性的求偶发声以及另外两种行为表现出雄性化。左侧SDApc总体积，最重要的是左侧神经元数量，与发声率相关。未发现行为与立体学估计之间的其他侧化相关性。得出的结论是，各种立体学参数以及发声行为的侧化和脑不对称取决于雄激素早期的性分化作用。有人提出，在沙鼠中，雄激素在一个侧化不对称的下丘脑核团中间神经元的存活中起作用，该核团是发声控制的一个指标。
