Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
Brain Res. 2021 Nov 1;1770:147628. doi: 10.1016/j.brainres.2021.147628. Epub 2021 Aug 26.
The amygdala is central to emotional behavior, and the excitability level of the basolateral nucleus of the amygdala (BLA) is associated with the level of anxiety. The excitability of neuronal networks is significantly controlled by GABAergic inhibition. Here, we investigated whether GABAergic inhibition in the BLA is altered during the rat estrous cycle. In rat amygdala slices, most principal BLA neurons display spontaneous IPSCs (sIPSCs) in the form of "bursts" of inhibitory currents, occurring rhythmically at a frequency of about 0.5 Hz. The percentage of BLA neurons displaying sIPSC bursts, along with the inhibitory charge transferred by sIPSCs and the frequency of sIPSC bursts, were significantly increased during the estrus phase; increased inhibition was accompanied by reduced anxiety in the open field, the light-dark box, and the acoustic startle response tests. sIPSC bursts were blocked by ibuprofen, an antagonist of acid-sensing-1a channels (ASIC1a), whose activity is known to increase by decreasing temperature. A transient reduction in the temperature of the slice medium, strengthened the sIPSCs bursts; this effect was blocked in the presence of ibuprofen. Further analysis of the sIPSC bursts during estrus showed significantly stronger rhythmic inhibitory activity in early estrus, when body temperature drops, compared with late estrus. To the extent that these results may relate to humans, it is suggested that "a calmer amygdala" due to increased inhibitory activity may underlie the positive affect in women around ovulation time. ASIC1a may contribute to increased inhibition, with their activity facilitated by the body-temperature drop preceding ovulation.
杏仁核是情绪行为的核心，杏仁核基底外侧核（BLA）的兴奋性水平与焦虑水平有关。神经元网络的兴奋性受 GABA 能抑制的显著控制。在这里，我们研究了在大鼠动情周期中 BLA 的 GABA 能抑制是否发生改变。在大鼠杏仁核切片中，大多数主要 BLA 神经元以抑制性电流“爆发”的形式显示自发性 IPSC（sIPSC），以约 0.5 Hz 的频率有节奏地发生。显示 sIPSC 爆发的 BLA 神经元的百分比，以及 sIPSC 传递的抑制电荷和 sIPSC 爆发的频率，在动情期显著增加；增加的抑制伴随着旷场、明暗箱和听觉惊吓反应测试中焦虑的减少。sIPSC 爆发被布洛芬阻断，布洛芬是酸感应 1a 通道（ASIC1a）的拮抗剂，其活性已知通过降低温度而增加。切片介质温度的短暂降低增强了 sIPSCs 爆发；在存在布洛芬的情况下，这种效应被阻断。对动情期 sIPSC 爆发的进一步分析表明，与动情晚期相比，体温下降时早期动情期的节律性抑制活性明显增强。在某种程度上，这些结果可能与人类有关，这表明由于抑制活性增加，“更平静的杏仁核”可能是排卵期间女性积极情绪的基础。ASIC1a 可能有助于增加抑制，其活性通过排卵前的体温下降得到促进。
