阻断5-HT1B受体对正常和帕金森病大鼠底丘脑核神经元活动的不同作用

目的观察体循环给予5-HT1B受体拮抗剂SB224289后,对正常大鼠和帕金森病(Parkinsons disease,PD)模型大鼠底丘脑核(subthalamic nucleus,STN)神经元电活动的影响。方法采用在体细胞外记录的方法,研究正常和PD大鼠STN神经元电活动的变化;比较阻断5-HT1B受体后两组大鼠STN神经元电活动的改变。结果①PD组大鼠STN神经元的平均放电频率(7.87±1.37)Hz]明显高于正常组大鼠(6.59±1.44)Hz,P<0.001]。两组大鼠STN神经元均表现为规则、不规则和暴发式放电3种形式。正常组大鼠具有规则、不规则和暴发式放电的神经元比例分别为33.33%、54.17%和12.50%;PD组分别为31.25%、35.42%和33.33%,PD组大鼠具有暴发式放电的神经元的百分比显著高于正常组(P<0.01)。②阻断5-HT1B受体后,正常大鼠STN神经元平均放电频率明显增高(P<0.01),具有暴发式放电的神经元数量显著增多(P<0.05)。而PD组大鼠阻断5-HT1B受体后STN神经元的放电频率和放电形式均无明显变化。结论 PD大鼠STN神经元呈过度兴奋状态;阻断5-HT1B受体可兴奋正常大鼠的STN神经元,而不影响PD大鼠的神经元活动。

Different effects of blocking 5-HT1B receptor on the activity of subthalamic nucleus neurons in normal rats and PD rats

Objective To study the effects of 5-HT1B receptor antagonist SB224289 in the circulation on neuronal activity of subthalamic nucleus(STN) neurons in normal rats and Parkinson’s disease(PD) rats.Methods By using in vivo extracellular recording,we investigated the changes of the firing activity of STN neurons in normal rats and PD rats and compared the changes of the firing activity of STN neurons after 5-HT1B receptor was blocked between these two groups.Results ① The average firing rate of STN neurons in PD rats(7.87±1.37)Hz was significantly higher than in the normal rats(6.59±1.44)Hz(P<0.001).STN neurons of rats in the two groups discharged in three forms: regular,irregular and bursts.In the normal rats,33.33% of STN neurons discharged regularly,54.17% irregularly and 12.50% in bursts.By contrast,in PD group,31.25% of STN neurons discharged regularly,35.42% irregularly and 33.33% in bursts,the percentage of STN neurons firing in bursts was obviously higher than that of the normal rats(P<0.01).② After blocking the 5-HT1B receptor,the average firing rate and the burst firing pattern of STN neurons in the normal rats increased significantly(P<0.01,P<0.05).However,neither the firing rate nor the pattern showed significant change in PD group.Conclusion STN neurons are over-active in PD rats.Blocking the 5-HT1B receptor excites the STN neurons of normal rats;however,it does not affect the neuronal activity of PD rats.