小鼠脊髓背角Ⅰ层-PAG投射神经元短时程突触可塑性的特征研究  

Characteristics of short-term synaptic plasticity of spino-PAG projection neurons in the lamina Ⅰ of spinal dorsal horn of mice

作　　者：韩文娟[1] 赵芝威 杜祎康 肖梅梅 解柔刚[1] 罗层[1] 

机构地区：[1]第四军医大学基础部神经生物学教研室暨脑科学协同创新中心,西安710032 [2]第四军医大学学员1旅,2014级西安710032 [3]潍坊人民医院麻醉科,潍坊261041

出　　处：《神经解剖学杂志》2017年第2期111-116,共6页Chinese Journal of Neuroanatomy

基　　金：国家自然科学基金(31471059;31671088;31400949);陕西省自然科学基金项目(2014JQ4127)

摘　　要：目的:研究小鼠脊髓背角Ⅰ层向中脑导水管周围灰质(periaquaductal gray,PAG)投射神经元在双脉冲刺激下表现出来的短时程突触可塑性的特点。方法:选取18~21 d C57/Bl6小鼠,脑立体定位注射2.5%Di I(100 nl)至PAG,2~3 d后制备400~650μm带背根的脊髓薄片,孵育1 h后用全细胞膜片钳技术记录Di Ⅰ阳性标记的脊髓背角Ⅰ层向PAG投射(spino-PAG)神经元,在判断其为单突触传递后,给予时间间隔为110 ms的双脉冲刺激诱致刺激外周C纤维诱发的C-e EPSCs,观察其短时程突触可塑性的特点。结果:(1)应用脑立体定位注射技术向PAG注射荧光素Di Ⅰ后可在脊髓背角Ⅰ层检测到逆行标记的神经元,提示该神经元为向PAG投射的神经元(spino-PAG投射神经元)。(2)在给予脊神经背根时间间隔为110 ms的双脉冲刺激后,脊髓背角Ⅰ层spino-PAG投射神经元发生不同程度和性质的短时程突触可塑性改变。其中,52.8%(28/53)的神经元表现为短时程的双脉冲易化(paired-pulse facilitation,PPF),其PPR的平均值为1.76±0.18;47.2%(25/53)的神经元表现为短时程的双脉冲抑制(paired-pulse depression,PPD),其PPR的平均值为0.61±0.05。结论:双脉冲刺激脊神经背根诱致C-e EPSCs可使脊髓背角I层spino-PAG神经元呈现短时程易化和短时程抑制的突触可塑性特征,提示这种短时程突触可塑性可能在痛信息的传递和敏化过程中发挥重要作用。Objective：To study the characteristics of short-term synaptic plasticity of the spino-periaquaductal gray （PAG） projection neurons in the lamina Ⅰ of spinal dorsal horn of mouse.Methods：C57/Bl6 mice at 18-21 d were placed in a stereotaxic apparatus,receiving a single injection of 100 nl of 2.5% DiI into the right PAG.After a 2-3 d survival period,transverse 400-650 μm thick spinal cord slices with dorsal roots attached were obtained.The slices were stored in an incubation solution at room temperature for 1 h,and then transferring to a recording solution.Standard wholecell patch clamp recordings were performed in the DiI-labelled spino-PAG projection neurons from lamina Ⅰ of the spinal dorsal horn.To measure excitatory postsynaptic currents （EPSCs） from labelled neurons in lamina Ⅰ,dorsal root was stimulated with pairs of stimulus with inter-stimulus interval of 110 ms at C-fiber intensity through a suction electrode with an isolated current stimulator.Characteristics of short-term synaptic plasticity were explored.Results：（1） With the stereotaxic injection of DiI into right PAG,a subpopulation of neurons can be labelled with DiI in spinal lamina Ⅰ,indicating that these were spino-PAG projection neurons.（2） The spino-PAG projection neurons in spinal lamina Ⅰ display a shortterm synaptic plasticity by stimulation of dorsal root with pairs of stimulus at inter-stimulus interval of 110 ms.52.8% of the spino-PAG projection neurons tested （28/53） display a paired-pulse facilitation （PPF）,with an average of PPR at 1.76 ± 0.18.47.2% （25/53） of the neurons tested display a paired-pulse depression （PPD）,with an average of PPR at 0.61 ±0.05.Conclusions：Paired-pulse stimulation of the dorsal root can induce short-term facilitation or short-term depression of C-eEPSCs recorded in spino-PAG projection neurons in spinal lamina Ⅰ,suggesting that short-term synaptic plasticity may play an important role in the transmission and sensitization of pain signals.

关 键 词：脊髓背角 投射神经元 短时程突触可塑性 突触传递易化 突触传递抑制 小鼠 

分 类 号：R338[医药卫生—人体生理学]