Effects of electrical stimulation of dorsal raphe nucleus on neuronal response properties of barrel cortex layer IV neurons following long-term sensory deprivation

背缝神经核的电刺激对经过长期感觉剥夺的大鼠皮层IV层神经元的神经应答特性的影响(英文)

Objective To evaluate the effect of electrical stimulation of dorsal raphe nucleus（DRN）on response properties of layer IV barrel cortex neurons following long-term sensory deprivation.Methods Male Wistar rats were divided into sensory-deprived（SD）and control（unplucked）groups.In SD group,all vibrissae except the D2 vibrissa were plucked on postnatal day one,and kept plucked for a period of 60 d.After that,whisker regrowth was allowed for 8-10 d.The D2 principal whisker（PW） and the D1 adjacent whisker（AW）were either deflected singly or both deflected in a serial order that the AW was deflected 20 ms before PW deflection for assessing lateral inhibition,and neuronal responses were recorded from layer IV of the D2 barrel cortex.DRN was electrically stimulated at inter-stimulus intervals（ISIs）ranging from 0 to 800 ms before whisker deflection.Results PW-evoked responses increased in the SD group with DRN electrical stimulation at ISIs of 50 ms and 100 ms,whereas AW-evoked responses increased at ISI of 800 ms in both groups.Whisker plucking before DRN stimulation could enhance the responsiveness of barrel cortex neurons to PW deflection and decrease the responsiveness to AW deflection. DRN electrical stimulation significantly reduced this difference only in PW-evoked responses between groups.Besides,no DRN stimulation-related changes in response latency were observed following PW or AW deflection in either group.Moreover, condition test（CT）ratio increased in SD rats,while DRN stimulation did not affect the CT ratio in either group.There was no obvious change in 5-HT2A receptor protein density in barrel cortex between SD and control groups.Conclusion These results suggest that DRN electrical stimulation can modulate information processing in the SD barrel cortex.

目的本文旨在研究长期感觉剥夺后,背缝神经核的电刺激对桶状皮层(barrel cortex)IV层神经元的神经应答特性的影响。方法雄性Wistar大鼠分为感觉剥夺组(sensory-deprived,SD)和对照组。SD组大鼠从出生开始,左半脸所有胡须(D2胡须除外)均被拔除,并维持60天。在之后的8-10d内,允许胡须重新生长。对背缝神经核给予电刺激,之后偏转胡须,记录D2桶状皮层IV层神经元的神经应答。结果当给予的电刺激的间距为50 ms和100 ms时,电刺激能增强SD大鼠主须(principal whisker,PW)偏转引起的神经应答,而当给予的电刺激的间距为800 ms时,电刺激能增强SD组和对照组大鼠邻近胡须(adjacent whisker,AW)偏转引起的神经应答。与对照组相比,胡须的拔除能增强桶状皮层对PW偏转的应答,而削弱其对AW偏转的应答。此外,PW或AW偏转后,在两组中均未发现与背缝神经核的电刺激相关的反应潜伏期的变化。与对照组相比,SD大鼠的桶状皮层中5-HT2A受体的表达水平无明显差异。结论背缝神经核的电刺激能调节感觉剥夺的桶状皮层的信息处理。