Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA.
Graduate Program in Biology, North Carolina State University, Raleigh, North Carolina, USA.
J Comp Neurol. 2023 May;531(7):759-774. doi: 10.1002/cne.25460. Epub 2023 Feb 9.
An important factor that can modulate neuron properties is sex-specific hormone fluctuations, including the human menstrual cycle and rat estrous cycle in adult females. Considering the striatal brain regions, the nucleus accumbens (NAc) core, NAc shell, and caudate-putamen (CPu), the estrous cycle has previously been shown to impact relevant behaviors and disorders, neuromodulator action, and medium spiny neuron (MSN) electrophysiology. Whether the estrous cycle impacts MSN dendritic spine attributes has not yet been examined, even though MSN spines and glutamatergic synapse properties are sensitive to exogenously applied estradiol. Thus, we hypothesized that MSN dendritic spine attributes would differ by estrous cycle phase. To test this hypothesis, brains from adult male rats and female rats in diestrus, proestrus AM, proestrus PM, and estrus were processed for Rapid Golgi-Cox staining. MSN dendritic spine density, size, and type were analyzed in the NAc core, NAc shell, and CPu. Overall spine size differed across estrous cycle phases in female NAc core and NAc shell, and spine length differed across estrous cycle phase in NAc shell and CPu. Consistent with previous work, dendritic spine density was increased in the NAc core compared to the NAc shell and CPu, independent of sex and estrous cycle. Spine attributes in all striatal regions did not differ by sex when estrous cycle was disregarded. These results indicate, for the first time, that estrous cycle phase impacts dendritic spine plasticity in striatal regions, providing a neuroanatomical avenue by which sex-specific hormone fluctuations can impact striatal function and disorders.
一个可以调节神经元特性的重要因素是性别特异性激素波动，包括人类的月经周期和成年雌性大鼠的动情周期。考虑到纹状体脑区，包括伏隔核（NAc）核心、NAc 壳和尾壳核（CPu），动情周期以前被证明会影响相关行为和疾病、神经调质作用以及中间神经元（MSN）电生理学。尽管 MSN 棘突和谷氨酸能突触的特性对外源性应用的雌二醇敏感，但动情周期是否会影响 MSN 树突棘属性尚未被检测到。因此，我们假设 MSN 树突棘属性会因动情周期阶段而异。为了验证这一假设，对处于间情期、发情前期 AM、发情前期 PM 和发情期的成年雄性大鼠和雌性大鼠的大脑进行了快速高尔基染色处理。在 NAc 核心、NAc 壳和 CPu 中分析了 MSN 树突棘密度、大小和类型。在雌性 NAc 核心和 NAc 壳中，整个发情周期阶段的 MSN 树突棘大小不同，在 NAc 壳和 CPu 中，发情周期阶段的 MSN 棘突长度不同。与之前的工作一致，NAc 核心中的树突棘密度高于 NAc 壳和 CPu，与性别和发情周期无关。当不考虑发情周期时，所有纹状体区域的棘突属性不因性别而异。这些结果首次表明，发情周期阶段会影响纹状体区域的树突棘可塑性，为性别特异性激素波动影响纹状体功能和疾病提供了一个神经解剖学途径。
