Sexually dimorphic synaptic organization of the medial amygdala
Sexually dimorphic synaptic organization of the medial amygdala
复制标题
DOI：
10.1523/jneurosci.2919-05.2005
复制
发表时间：
2005-11-16
影响因子：
5.3
通讯作者：
Woolley, CS
中科院分区：
文献类型：
--
作者：
Cooke, BM;Woolley, CS
内侧杏仁核在社会行为中很重要，其中许多在男性和女性之间是不同的。内侧杏仁核的后背侧亚核（MeApd）对性腺类固醇激素特别敏感，并且可能是性二态社会行为的性腺激素调节部位。在这里，我们表明，在大鼠的MeApd的突触组织是性二态性和偏侧青春期前。使用全细胞电压钳记录和定量电子显微镜，我们发现，特别是在左半球，青春期前的男性有类似的80%以上的兴奋性突触每MeApd神经元比女性。在左侧而不是右侧MeApd，男性的微型EPSC（mEPSC）频率显著高于女性; mEPSC振幅没有性别二态性。成对脉冲促进的EPSC，释放概率的指数，也没有性别二态性，这表明更大的mEPSC频率是由兴奋性突触数量的差异。电子显微镜证实，不对称的突触神经元的比例和总的不对称突触数量显着大于男性的左侧MeApd比女性。与兴奋性突触的结果相反，我们没有发现抑制性突触中存在性二型性或偏侧性的证据。无论是频率还是振幅的mIPSC是性二态性或偏侧。同样，用电子显微镜测量的对称突触的数量也不是性别二型的。这些结果表明，左侧MeApd的兴奋性突触组织在青春期前是性分化的，这可能为激素对成年社会行为的影响提供了性二态性神经基质。
The medial amygdala is important in social behaviors, many of which differ between males and females. The posterodorsal subnucleus of the medial amygdala (MeApd) is particularly sensitive to gonadal steroid hormones and is a likely site for gonadal hormone regulation of sexually dimorphic social behavior. Here we show that the synaptic organization of the MeApd in the rat is sexually dimorphic and lateralized before puberty. With the use of whole-cell voltage-clamp recording and quantitative electron microscopy, we found that, specifically in the left hemisphere, prepubertal males have similar to 80% more excitatory synapses per MeApd neuron than females. In the left but not the right MeApd, miniature EPSC (mEPSC) frequency was significantly greater in males than in females; mEPSC amplitude was not sexually dimorphic. Paired-pulse facilitation of EPSCs, an index of release probability, also was not sexually dimorphic, suggesting that greater mEPSC frequency is caused by a difference in excitatory synapse number. Electron microscopy confirmed that the asymmetric synapse-to-neuron ratio and the total asymmetric synapse number were significantly greater in the left MeApd of males than of females. In contrast to results for excitatory synapses, we found no evidence of sexual dimorphism or laterality in inhibitory synapses. Neither the frequency nor the amplitude of mIPSCs was sexually dimorphic or lateralized. Likewise, the number of symmetric synapses measured with electron microscopy was not sexually dimorphic. These findings show that the excitatory synaptic organization of the left MeApd is sexually differentiated before puberty, which could provide a sexually dimorphic neural substrate for the effects of hormones on adult social behavior.