Dale Nathan J, Cao Jinyan, Dorris David M, Crawford Ashtin B, Meitzen John
Department of Biological Sciences, North Carolina State University, Campus Box 7617, Raleigh, NC, 27695-7617, USA.
Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA.
Brain Struct Funct. 2025 Aug 6;230(7):127. doi: 10.1007/s00429-025-02995-5.
In the adult mammalian nervous system, sex differences can be manifested independently or in concert with sex-specific hormone cycles, such as the rat estrous cycle. Biological sex and related cycles influence neuronal properties in many brain regions, including the striatum, encompassing the nucleus accumbens (NAc) core, NAc shell, and caudate-putamen (CPu). While neuron soma size and density are commonly assessed in the context of biological sex, these attributes have never been investigated in the striatal regions of adult gonad-intact rodents disaggregated by sex and estrous cycle phase. Thus, we tested the hypothesis that neuron soma size and density would vary by striatal region, sex, and estrous cycle phase. Neuron soma size and density were measured in NAc core, NAc shell, and CPu from adult male rats and female rats in diestrus, proestrus, and estrus phases. Overall, neuron soma size was larger in the CPu than the NAc core and shell. Neuron density was greatest in the NAc shell, followed by the NAc core and CPu. Regarding sex, soma size was larger in male than female NAc shell and did not differ in other regions. Soma density did not sexually differ. Neither soma size nor density differed across estrous cycle phases. These results provide, for the first time, striatal neuron size and density measurements disaggregated by sex and estrous cycle phase and an indication of a sex difference in NAc shell soma size. In contrast, the estrous cycle appears to influence striatal function via other mechanisms than neuronal soma attributes.
在成年哺乳动物的神经系统中，性别差异可以独立表现，也可以与特定性别的激素周期协同表现，比如大鼠的发情周期。生物性别及相关周期会影响许多脑区的神经元特性，包括纹状体，其包含伏隔核（NAc）核心、NAc壳和尾状核 - 壳核（CPu）。虽然神经元胞体大小和密度通常是在生物性别的背景下进行评估的，但这些属性从未在按性别和发情周期阶段分类的成年性腺完整啮齿动物的纹状体区域中进行过研究。因此，我们检验了这样一个假设，即神经元胞体大小和密度会因纹状体区域、性别和发情周期阶段而异。我们测量了成年雄性大鼠以及处于动情间期、动情前期和动情期的成年雌性大鼠的NAc核心、NAc壳和CPu中的神经元胞体大小和密度。总体而言，CPu中的神经元胞体大小大于NAc核心和壳。神经元密度在NAc壳中最大，其次是NAc核心和CPu。在性别方面，雄性NAc壳中的胞体大小大于雌性，而在其他区域则没有差异。胞体密度没有性别差异。胞体大小和密度在发情周期各阶段均无差异。这些结果首次提供了按性别和发情周期阶段分类的纹状体神经元大小和密度测量数据，并表明NAc壳胞体大小存在性别差异。相比之下，发情周期似乎是通过神经元胞体属性以外的其他机制影响纹状体功能。
