雄激素对成年雄性斑胸草雀前脑高级发声中枢-弓状皮质栎核通路长时程压抑的影响

Effects of androgens on the long-term depression of HVC-RA pathway in adult male zebra finches

雄激素可通过调控鸣唱控制系统改变鸣禽的鸣唱行为。本研究以成年雄性斑胸草雀为实验动物,采用在体电生理实验方法,观察雄激素对高级发声中枢(high vocal center,HVC)-弓状皮质栎核(robust nucleus of the arcopallium,RA)通路突触可塑性的影响,以期阐明雄激素对成年鸣禽鸣唱稳定性维持的神经生理机制。将实验动物分为对照组、去势组与去势+埋植睾酮组,分别记录高频刺激(400 Hz,2 s)HVC后,HVC-RA通路长时程压抑(long-term depression,LTD)的变化以及双脉冲易化效应。结果显示,高频刺激HVC,在对照组可以记录到LTD现象;去势组中仅有短时程压抑(short-term depression,STD)现象;去势+埋植睾酮组中LTD现象则恢复。双脉冲易化现象在去势组不明显,而对照组和去势+埋植睾酮组易化率明显高于去势组。以上结果提示,雄激素可能通过影响成年雄性斑胸草雀HVC-RA通路的LTD水平来维持鸣曲稳定性,并对该通路的短时程突触可塑性有一定的调节作用。

Androgens can affect the singing behavior via regulating the song control system. In the present study, the effect of androgen on the synaptic plasticity of high vocal center （HVC）-robust nucleus of the arcopallium （RA） pathway was investigated through electrophysiological recording in vivo. We divided the adult male zebra finches into control, castration and castration plus testosterone implantation groups. The changes of long-term depression （LTD） and the paired-pulse facilitation in HVC-RA pathway induced by high-frequency （400 Hz, 2 s） stimulation of HVC were recorded, respectively. The results showed that high-frequency stimulation could effectively induce LTD in control group, but only evoke short-term depression in the castration group. In castration plus testos- terone implantation group, LTD was restored. The paired-pulse facilitation was not obvious in the castration group, whereas it was significantly improved in the control and castration plus testosterone implantation groups. These results suggest that androgens may maintain the stability of song by influencing the level of LTD in HVC-RA pathway in adult male zebra finches, and androgens can affect the short-term synaptic plasticity of HVC-RA pathway.