Neuropsychopharmacology & Psychobiology Research Group, Department of Neuroscience, University of Cádiz, 11003, Cádiz, Spain.
Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III, 28029, Madrid, Spain.
Biol Sex Differ. 2023 Sep 28;14(1):64. doi: 10.1186/s13293-023-00550-7.
In addition to social and cultural factors, sex differences in the central nervous system have a critical influence on behavior, although the neurobiology underlying these differences remains unclear. Interestingly, the Locus Coeruleus (LC), a noradrenergic nucleus that exhibits sexual dimorphism, integrates signals that are related to diverse activities, including emotions, cognition and pain. Therefore, we set-out to evaluate sex differences in behaviors related to LC nucleus, and subsequently, to assess the sex differences in LC morphology and function.
Female and male C57BL/6J mice were studied to explore the role of the LC in anxiety, depressive-like behavior, well-being, pain, and learning and memory. We also explored the number of noradrenergic LC cells, their somatodendritic volume, as well as the electrophysiological properties of LC neurons in each sex.
While both male and female mice displayed similar depressive-like behavior, female mice exhibited more anxiety-related behaviors. Interestingly, females outperformed males in memory tasks that involved distinguishing objects with small differences and they also showed greater thermal pain sensitivity. Immunohistological analysis revealed that females had fewer noradrenergic cells yet they showed a larger dendritic volume than males. Patch clamp electrophysiology studies demonstrated that LC neurons in female mice had a lower capacitance and that they were more excitable than male LC neurons, albeit with similar action potential properties.
Overall, this study provides new insights into the sex differences related to LC nucleus and associated behaviors, which may explain the heightened emotional arousal response observed in females.
除了社会和文化因素外，中枢神经系统中的性别差异对行为有至关重要的影响，尽管这些差异的神经生物学基础仍不清楚。有趣的是，蓝斑（LC），一个表现出性别二态性的去甲肾上腺素能核团，整合了与多种活动相关的信号，包括情绪、认知和疼痛。因此，我们着手评估与 LC 核相关的行为中的性别差异，随后评估 LC 形态和功能的性别差异。
研究了雌性和雄性 C57BL/6J 小鼠，以探索 LC 在焦虑、抑郁样行为、幸福感、疼痛以及学习和记忆中的作用。我们还探索了每只性别的去甲肾上腺素能 LC 细胞数量、它们的树突体体积以及 LC 神经元的电生理特性。
尽管雄性和雌性小鼠都表现出类似的抑郁样行为，但雌性小鼠表现出更多的焦虑相关行为。有趣的是，在涉及区分具有细微差异的物体的记忆任务中，雌性比雄性表现出更好的记忆力，并且它们对热痛的敏感性也更高。免疫组织化学分析表明，雌性的去甲肾上腺素能细胞较少，但树突体体积比雄性大。膜片钳电生理学研究表明，雌性 LC 神经元的电容较低，比雄性 LC 神经元更易兴奋，尽管它们的动作电位特性相似。
总的来说，这项研究为与 LC 核相关的性别差异以及相关行为提供了新的见解，这可能解释了女性中观察到的更高的情绪唤醒反应。
