5,7-双羟色胺损毁大鼠中缝背核后底丘脑核的神经活动增强

采用玻璃微电极在体细胞外记录法,观察了5,7-双羟色胺(5,7-dihydroxytryptamine,5,7-DHT)损毁大鼠中缝背核(dorsalraphenucleus,DRN)后,底丘脑核(subthalamicnucleus,STN)神经元电活动的变化。结果发现,对照组和DRN损毁组大鼠STN神经元的放电频率分别是(6.93±6.55)Hz和(11.27±9.31)Hz,DRN损毁组大鼠的放电频率显著高于对照组(P<0.01)。在对照组大鼠,13%的神经元呈现规则放电,46%为不规则放电,41%为爆发式放电;而在DRN损毁组大鼠,具有规则、不规则和爆发式放电的神经元比例分别为9%、14%和77%,爆发式放电的STN神经元比例明显高于对照组(P<0.01)。结果显示,DRN损毁后大鼠STN神经元的放电频率增高,爆发式放电增多,提示在正常大鼠DRN抑制STN神经元的活动。

Increased subthalamic neuronal activity after dorsal raphe nucleus lesion by 5,7-dihydroxytryptamine in the rat

In vivo extracellular recordings were made in the subthalamic nucleus (STN) of intact control rats and rats with 5,7-dihydroxytryptamine (5,7-DHT) -produced lesion of dorsal raphe nucleus (DRN). The results showed that the firing rate of STN neurons in control rats and DRN-lesioned rats were (6.93+/-6.55) Hz and (11.27+/-9.31) Hz, respectively, and the firing rate of DRN-lesioned rats significantly increased when compared to the control rats (P<0.01). In control rats, 13% of STN neurons discharged regularly, 46% irregularly and 41% in bursts. In DRN-lesioned rats, 9% of STN neurons discharged regularly, 14% irregularly and 77% in bursts, the percentage of STN neurons firing in bursts was obviously higher than that of the control rats (P<0.01). In addition, the mean interspike interval coefficient of variation of STN neurons in control rats and DRN-lesioned rats were (0.05+/-0.04) and (0.11+/-0.09), respectively. The mean interspike interval coefficient of variation of DRN-lesioned rats was significantly higher than that of the control rats (P<0.001). These results show that the firing rate and the bursting pattern rate of neurons in STN of DRN-lesioned rats increase significantly, suggesting that DRN inhibits the neuronal activity of the subthalamic neurons in the intact rat.