丘脑底核orexin-B对正常小鼠运动行为调控及机制

EFFECT OF OREXIN-B IN THE SUBTHALAMIC NUCLEUS IN REGULATING MOTOR BEHAVIOR IN NORMAL MICE AND RELATED MECHANISM

目的探究丘脑底核orexin-B对正常小鼠运动行为的调控及神经元自发放电的影响。方法分别采用爬杆实验、旷场实验和在体细胞外电生理记录等方法,观察丘脑底核微量注射orexin-B对小鼠运动的调控以及神经元自发放电的影响。结果双侧丘脑底核注射orexin-B可以明显延长正常小鼠爬杆转头时间(t=2.40,P<0.05)和爬杆时间(t=4.59,P<0.01)。旷场实验结果显示,双侧丘脑底核注射orexin-B显著减少小鼠运动总距离(t=3.14,P<0.01)。在正常小鼠丘脑底核记录到11个神经元,微压力注射orexin-B使其中7个神经元的放电频率显著升高(t=4.96,P<0.01),放电频率平均升高(216.90±118.40)%,与生理盐水对照组比较差异有显著性(Z=-2.72,P<0.01)。结论 Orexin-B能增加丘脑底核神经元自发放电,抑制正常小鼠的运动行为,可能通过丘脑底核参与基底神经节间接通路的调控运动。

Objective To investigate the effect of orexin-B in the subthalamic nucleus on motor behavior and neuronal spontaneous discharge in normal mice.Methods The pole test,the open field test,and thein vivo extracellular electrophysiological recordings were used to observe the effect of orexin-B microinjection into the subthalamic nucleus on motor behavior and neuronal spontaneous discharge in mice.Results In the pole test,orexin-B microinjection into the bilateral subthalamic nucleus significantly increased the time to turn around(t=2.40,P<0.05)and the total time to climb down the pole(t=4.59,P<0.01).The open field test showed that orexin-B microinjection into the bilateral subthalamic nucleus significantly reduced the total distance travelled by the mice(t=3.14,P<0.01).A total of 11neurons5were recorded in the subthalamic nucleus of normal mice;micropressure injection of orexin-B significantly increased the neuronal discharge frequency of 7out of the 11neurons(t=4.96,P<0.01)by an average increase of(216.90±118.40)%,and there was a significant difference between this group and the normal saline group(Z=-2.72,P<0.01).Conclusion Orexin-B can increase the spontaneous discharge of neurons in the subthalamic nucleus and inhibit the motor behavior of normal mice,suggesting that orexin-B can regulate the movement through the indirect pathway of basal ganglia which involves the subthalamic nucleus.