大鼠慢性心肌梗死对前额叶皮质锥体细胞突触活性影响的电生理学研究

目的:检测大鼠满性心肌梗死所致心绞痛之后,内侧前额叶皮质(medial prefrontal cortex,mPFC)锥体细胞突触传递活性的变化,探讨调节慢性心绞痛可能的中枢机制。方法:雄性成年SD大鼠随机分为假手术组和慢性心肌梗死(chronic myocardial infarction,CMI)手术组,每组5只。手术2周后,制备mPFC区域急性脑片,通过全细胞膜片钳方法记录锥体细胞的兴奋性和抑制性突触电流,比较假手术组和手术组的突触电流活性变化。结果:相较于假手术组动物,手术组动物mPFC内兴奋性突触电流传递明显增强,抑制性突触电流传递明显减弱。同时抑制性中间神经元动作电位释放下降。结论:CMI之后mPFC内锥体细胞的兴奋性突触信号传递增强,可能是由于局部抑制性神经元活性降低所致。鉴于mPFC内锥体细胞活性对于镇痛具有正向效应,这种变化对于mPFC对慢性心绞痛的中枢抑制可能具有积极的意义。

Electrophysiological study of the synaptic transmission of pyramidal cells in the medial prefrontal cortex of rats with chronic myocardial infarction

Objective:Explore the possible changed synaptic transmission in the pyramidal cells of the medial prefrontal cortex (mPFC) after chronic myocardial infarction (CMI) of rats.Methods:Ten adult male SD rats were divided into sham group and CMI group (n =5 in each group).Two weeks after surgery,the synaptic transmission of pyramidal cells in the mPFC were studied by whole cell patch recording method.Results:In pyramidal cells of rats with CMI group,both the spontaneous and electrical evoked excitatory post-synaptic currents (EPSC) was greatly enhanced,while the inhibitory post-synaptic current (IPSC) were inhibited.Meanwhile,the spike release of the GABAergic interneurons were reduced.Conclusion:The excitatory inputs to the pyramidal cells were greatly enhanced in the rats with CMI,which may due to the reduced local GABAergic activity.Since activation of pyramidal cells in the mPFC induce analgesia,the enhanced excitatory inputs to the pyramidal cells may be meaningful for the central inhibition of the CMI induced angina.