摘要
【目的】从电生理学角度研究六价铬对牛蛙心脏、腓肠肌和坐骨神经干动作电位的影响,探讨六价铬的毒性作用机制。【方法】将不同浓度重铬酸钾溶液通过腹腔注射和离体心脏灌流法处理牛蛙心脏,测定六价铬对在体和离体心脏心率和收缩力的影响。用重铬酸钾溶液浸润好的纱布包裹腓肠肌,测定腓肠肌收缩力变化。采用细胞外电极引导法,测定六价铬对坐骨神经干动作电位传导速度的影响。【结果】结果显示:重铬酸钾对心率和收缩力具有抑制作用,机制分别与六价铬抑制T型钙通道活性和L型钙通道活性有关;然而1 mg/L铬对在体蛙心作用15 min至30 min后,心率增加,可能是“毒物兴奋效应”所致;0.001 mg/L至10 mg/L六价铬对腓肠肌收缩力具有浓度依赖性增强作用,表现为正性变力效应,可能是“毒物兴奋效应”的结果;100 mg/L六价铬抑制了腓肠肌收缩力,表现为负性变力效应,机制与六价铬对兰尼碱受体(Ryanodine receptor,RyR)的抑制作用有关;六价铬以质量浓度和时间依赖性降低了神经干动作电位传导速度,机制与六价铬对电压门控Na+通道产生的失活作用有关。【结论】六价铬对心肌、骨骼肌和神经均具有毒性作用,结果可为六价铬的毒性作用研究提供一定的电生理实验依据。
【Proposes】To investigate the toxicological mechanism of hexavalent chromium,the ef⁃fects of hexavalent chromium on the heart,gastrocnemius muscle and action potential of sciatic nerve trunk in bullfrog were studied from the perspective of electrophysiology.【Methods】The bullfrog hearts were treated with different concentrations of potassium dichromate solution by intraperitoneal in⁃jection and isolated heart perfusion,and the effects of hexavalent chromium on heart rate and contrac⁃tility in vivo and in vitro were determined.The gastrocnemius muscle was wrapped with a gauze soaked in potassium dichromate solution,and the contractility of gastrocnemius muscle was mea⁃sured.The effect of hexavalent chromium on conduction velocity of sciatic nerve trunk was measured by extracellular electrode guidance.【Findings】The results show that potassium dichromate has an in⁃hibitory effect on heart rate and contractility,and the mechanism may be related to the inhibition of T-type and L-type calcium channels activity by hexavalent chromium;However,1 mg/L chromium increases the heart rate of in vivo frog heart after 15 to 30 min,which may be due to the“hormetic ef⁃fect”;0.001 to 10 mg/L hexavalent chromium has a concentration-dependent enhancement effect on gas⁃trocnemius contractility,showing a positive inotropic effect,which may be the result of“hormetic effect”;Hexavalent chromium at 100 mg/L inhibits the gastrocnemius contractility,showing a negative inotro⁃pic effect,the mechanism is related to the inhibitory effect of hexavalent chromium on ryanodine recep⁃tor(RyR);Hexavalent chromium reduces the conduction velocity of sciatic nerve trunk action poten⁃tial in a concentration and time-dependent manner,and the mechanism was related to the inactivation of voltage-gated Na+channels by hexavalent chromium.【Conclusions】Hexavalent chromium has tox⁃icity on heart,skeletal muscle,and nerve,which could provide some electrophysiological experimen⁃tal basis for the toxicity study of hexa
作者
张艳君
张敬
张全有
李明臻
李鹏翠
卫小春
陈维毅
ZHANG Yanjun;ZHANG Jing;ZHANG Quanyou;LI Mingzhen;LI Pengcui;WEI Xiaochun;CHEN Weiyi(College of Biomedical Engineering,Taiyuan University of Technology,Jinzhong 030600,China;College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Provincial Key Laboratory for Repair of Bone and Soft Tissue Injury,The Second Hospital of Shanxi Medical University,Taiyuan 030001,China)
出处
《太原理工大学学报》
CAS
北大核心
2024年第2期365-375,共11页
Journal of Taiyuan University of Technology
基金
国家自然科学基金资助项目(11702093)
山西省基础研究计划资助项目(202203021211124)。
关键词
六价铬
收缩力
电位传导速度
心脏
骨骼肌
坐骨神经干
hexavalent chromium
contractility
conduction velocity of action potential
heart
skeletal muscle
sciatic nerve trunk
