中央杏仁核对大鼠心脏伤害性感受的调节作用

摘要

目的：观察电刺激大鼠中央杏仁核(CeA)对心脏伤害性感受的调节作用。方法选择成年雄性 SD大鼠，以心包内注射辣椒素(CAP)诱发的大鼠背斜方肌肌电为指标，制备心脏痛动物模型；对照组分为正常对照组和心包内注射生理盐水对照组。利用免疫组织化学方法观察心脏痛模型大鼠 CeA内 c-fos 表达的变化；并利用电生理学方法观察电刺激CeA(强度分别为30μA和70μA)对心包内注射CAP引起的肌电(EMG)反应的影响。结果①与正常对照组相比，心包内注射辣椒素组CeA内 c-fos 表达量显著升高且有统计学意义；正常对照组和心包内生理盐水对照组CeA内 c-fos表达量则无统计学差异；②30μA电刺激CeA后，大鼠背斜方肌的 EMG较对照组明显减弱，总放电率为对照组的(78.58±4.62)%(P<0.05)；70μA电刺激后总放电率为对照组的(54.89±3.98)%(P<0.05)。结论大鼠中央杏仁核可能参与了大鼠心脏伤害性感受信息的传入，且具有下行抑制性调节作用。%Objective To study the modulation of central amygdale (CeA)on cardiac nociception with electrical stimulation in rats.Methods The heart pain model of adult male Sprague-Dawley rats was established with intrapericardial injection of capsaicin; then the evoked electromyography (EMG ) responses in the spinotrapezius (SPT)were observed as an index.Immunohistochemical method was used to observe the expression of c-fos in CeA;The rats were divided into normal control group,intrapericardial saline injection control group,and intrapericardial capsaicin injection group. The changes of EMG responses after electrical stimulation on CeA (intensity of 30μA and 70μA)were observed separately by electrophysiology in different groups.Results① Compared with normal control group, intrapericardial capsaicin injection group had significantly increased expression of c-fos in CeA.However,c-fos expression did not differ significantly between intrapericardial saline injection group and normal control group;② After 30μA electrical stimulation on CeA,EMG response in SPT significantly decreased in intrapericardial capsaicin injection group compared with that in control group;the total discharge rate was (78.58±4.62)% of that of control group (P<0.05).After 70μA electrical stimulation on CeA, the total discharge rate was (54.89±3.98)% of that of control group (P<0.05).Conclusion CeA may be involved in cardiac nociceptive transmission in rats and has inhibitory effects on the modulation of rat cardiac nociception.