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本实验观察了39只切断迷走神经的家兔在电刺激下丘脑背内侧核(DMH)对心外膜直流电图和跨膜电位的影响。结果发现:电刺激DMH 5分钟引起显著的TQ段和ST段偏移(P<0.05),静息膜电位变小(P<0.05),动作电位幅度减少(P<0.05),时程缩短(P<0.05)和Vmax减慢(P<0.05),心肌组织乳酸浓度增加(P<0.01)。α-受体阻滞剂酚妥拉明能阻断上述变化。表明:刺激DMH能引起心肌缺血和缺血性心电变化,其机理可能主要由心交感α-受体冠脉收缩作用所致。
In the present study, the effects of dorsal medial nucleus of dorsal horn (DMH) in 39 vagotomized rabbits on epicardial DC and transmembrane potential were observed. The results showed that electrical stimulation of DMH for 5 min caused significant changes of TQ segment and ST segment (P <0.05), resting membrane potential decreased (P <0.05), amplitude of action potential decreased (P <0.05) P <0.05) and Vmax slowed down (P <0.05), and myocardial lactate concentration increased (P <0.01). Phentolamine, an alpha-blocker, blocks these changes. The results showed that: stimulation of DMH can cause myocardial ischemia and ischemic ECG changes, the mechanism may be mainly caused by cardiac sympathetic α-receptor coronary contractility.