急性瘙痒诱导的大鼠前扣带回皮层突触可塑性变化
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摘要
目的观察急性瘙痒诱导的大鼠前扣带回皮层(ACC)突触可塑性变化,探讨其在大脑皮层水平的发生机制。方法 12只6~8周龄SD大鼠随机均分为生理盐水组和组胺组。给予组胺组大鼠颈部皮内注射组胺(125μg/50μl),生理盐水组注射等容量生理盐水。5min后观察行为学变化,35min后断头取脑,做ACC冠状脑片。应用离体膜片钳技术记录ACC脑区Ⅱ~Ⅲ层锥体神经元微小兴奋性突触后电流(mEPSC)和微小抑制性突触后电流(mIPSC),分析ACC脑区兴奋性及突触可塑性变化。结果与生理盐水组比较,组胺组mEPSCs的频率和幅度明显升高(P<0.05),两组mIPSCs频率和幅度差异无统计学意义。结论急性瘙痒可使大鼠ACC脑区兴奋性提高,AMPA受体介导的mEPSC反应增强,而GABA受体介导的mIPSC反应无明显改变。
Objective To investigate the changes of synaptic plasticity in anterior cingulate cortex(ACC)after histamine-induced acute itch.Methods A total of 12 SD rats,aged 6-8weeks old,were randomly divided into saline group(n=6)and histamine group(n=6).Histamine(125μg/50μl)or saline(50μl)was injected intradermally into the nape of the animals.Five minutes later,itching behavior was estimated for 30 minutes.The animals were decapitated immediately after behavior test,and the coronal brain slices(350μm)containing ACC were prepared.Miniature excitatory postsynaptic current(mEPSC)and miniature inhibitory postsynaptic current(mIPSC)were recorded from the neurons in layerⅡ/Ⅲ of ACC for estimating the synaptic transmission.Results Both frequency and amplitude of mEPSCs were significantly greater in histamine group than those of saline group(P<0.05).There was no significant difference in frequency and amplitude of mIPSCs between two groups.Conclusion Our results suggest that AMPA receptor-mediated excitatory synaptic transmission in ACC is enhanced after acute itch,and the contribution of presynaptic and postsynaptic changes are both involved.However,GABA receptor-mediated inhibitory synaptic transmission is unaffected.
Objective To investigate the changes of synaptic plasticity in anterior cingulate cortex(ACC)after histamine-induced acute itch.Methods A total of 12 SD rats,aged 6-8weeks old,were randomly divided into saline group(n=6)and histamine group(n=6).Histamine(125μg/50μl)or saline(50μl)was injected intradermally into the nape of the animals.Five minutes later,itching behavior was estimated for 30 minutes.The animals were decapitated immediately after behavior test,and the coronal brain slices(350μm)containing ACC were prepared.Miniature excitatory postsynaptic current(mEPSC)and miniature inhibitory postsynaptic current(mIPSC)were recorded from the neurons in layerⅡ/Ⅲ of ACC for estimating the synaptic transmission.Results Both frequency and amplitude of mEPSCs were significantly greater in histamine group than those of saline group(P<0.05).There was no significant difference in frequency and amplitude of mIPSCs between two groups.Conclusion Our results suggest that AMPA receptor-mediated excitatory synaptic transmission in ACC is enhanced after acute itch,and the contribution of presynaptic and postsynaptic changes are both involved.However,GABA receptor-mediated inhibitory synaptic transmission is unaffected.
引文
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[8]宁丽,王英伟.在体膜片钳记录前扣带皮层神经元对伤害性电刺激的反应.临床麻醉学杂志,2012,28(11):1109-1111.
[9]Desbordesa G,Li A,Loqqia M,et al.Evoked itch perception is associated with changes in functional brain connectivity.Neuroimage Clin,2015,7:213-221.
[2]Drzezga A,Darsow U,Treede R D,et al.Central activation by histamine-induced itch:analogies to pain processing:a correlational analysis of O-15H2Opositron emission tomography studies.Pain,2001,92(1-2):295-305.
[3]Hsieh JC,Hagermark O,Stahle-backdahl M,et al.Urge to Scratch Represented in the Human Cerebral-Cortex during Itch.J Neurophysiol,1994,72(6):3004-3008.
[4]Mochizuki H,Tashiro M,Kano M,et al.Imaging of central itch modulation in the human brain using positron emission tomography.Pain,2003,105(1-2):339-346.
[5]Apkarian AV,Bushnell MC,Treede RD,et al.Human brain mechanisms of pain perception and regulation in health and disease.Eur J Pain,2005,9(4):463-484.
[6]马丽清,宁丽,王英伟.在体研究前扣带回皮层对伤害性热刺激的反应.临床麻醉学杂志,2013,29(7):693-695.
[7]Xu H,Wu LJ,Wang H,et al.Presynaptic and postsynaptic amplifications of neuropathic pain in the anterior cingulate cortex.J Neurosci,2008,28(29):7445-7453.
[8]宁丽,王英伟.在体膜片钳记录前扣带皮层神经元对伤害性电刺激的反应.临床麻醉学杂志,2012,28(11):1109-1111.
[9]Desbordesa G,Li A,Loqqia M,et al.Evoked itch perception is associated with changes in functional brain connectivity.Neuroimage Clin,2015,7:213-221.