Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90170-050, Brazil.
Department of Basic Sciences/Physiology, Federal University of Health Sciences, Porto Alegre, RS 90170-050, Brazil.
J Cell Sci. 2019 May 7;132(9):jcs227793. doi: 10.1242/jcs.227793.
The posterodorsal medial amygdala (MePD) is a sex steroid-sensitive area that modulates different social behavior by relaying chemosensorial information to hypothalamic nuclei. However, little is known about MePD cell type diversity and functional connectivity. Here, we have characterized neurons and synaptic inputs in the right and left MePD of adult male and cycling female (in diestrus, proestrus or estrus) rats. Based on their electrophysiological properties and morphology, we found two coexisting subpopulations of spiny neurons that are sexually dimorphic. They were classified as Class I (predominantly bitufted-shaped neurons showing irregular spikes with frequency adaptation) or Class II (predominantly stellate-shaped neurons showing full spike frequency adaptation). Furthermore, excitatory and inhibitory inputs onto MePD cells were modulated by sex, estrous cycle and hemispheric lateralization. In the left MePD, there was an overall increase in the excitatory input to neurons of males compared to cycling females. However, in proestrus, the MePD neurons received mainly inhibitory inputs. Our findings indicate the existence of hemispheric lateralization, estrous cycle and sexual dimorphism influences at cellular and synaptic levels in the adult rat MePD.
后背部内侧杏仁核（MePD）是一个对性别甾体敏感的区域，通过将化学感觉信息传递到下丘脑核来调节不同的社会行为。然而，关于 MePD 细胞类型多样性和功能连接知之甚少。在这里，我们描述了成年雄性和发情周期（动情前期、发情期或动情后期）雌性大鼠左右 MePD 中的神经元和突触输入。基于其电生理特性和形态，我们发现了两种共存的棘突神经元亚群，它们具有性别二态性。它们被分类为 I 类（主要是双树突状神经元，表现出不规则的频率适应的棘波）或 II 类（主要是星状神经元，表现出全频率适应的棘波）。此外，MePD 细胞上的兴奋性和抑制性输入受性别、发情周期和半球侧化的调节。在左侧 MePD 中，与发情周期的雌性相比，雄性神经元的兴奋性输入总体上增加。然而，在发情前期，MePD 神经元主要接收抑制性输入。我们的研究结果表明，成年大鼠 MePD 在细胞和突触水平上存在半球侧化、发情周期和性别二态性影响。
