摘要
用微电极技术研究不同浓度吗啡对豚鼠右心室乳头肌动作电位的作用及作用机制。低浓度吗啡(0.2—1.6 umol/L)使动作电位时程(APD)和有效不应期(ERP)缩短,呈剂量依赖性。此作用可被1μmol/L 纳洛酮、酚妥拉明,四乙胺和氯化铯阻断,但不能被异搏定阻断。高浓度吗啡(15—120μmol/L)则使 APD 和 ERP 延长,呈剂量依赖性,这作用不被1.2μmol/L纳洛酮阻断,但可被10μmol/L 纳洛酮、酚妥拉明、四乙胺、氯化铯和异搏定阻断。这些实验提示低浓度和高浓度的吗啡可能作用于不同的阿片受体亚型,低浓度吗啡的作用可能与钾通道有关,高浓度吗啡的作用可能与钾通道、钙通道或钙激活的钾通道有关。阿片受体的作用与α受体存在密切关系。
The effects of morphine at different concentrations on myocardial actionpotential were studied in isolated right ventricular papillary muscles of the guineapig.It was observed that morphine at low concentrations(0.2—1.6 μmol/L)shortened the action potential duration(ADP)and effective refractory period(ERP)in a concentration dependent manner.These effects could be abolishedby naloxone(1μmol/L),phentolamine,tetraethylammonium(TEA)and ce-sium chloride(Cs^+),but not by verapamil.On the other hand,morphine athigh concentrations(15—120 μmol/L)prolonged ADP and ERP in a concen-tration dependent manner.The effects were unaffected by low dose of naloxone(1.2/μmol/L)but were abolished by high dose of naloxone(10 μmol/L),phen-tolamine,TEA,Cs^+ and verapamil.These results suggest that morphine atlow and high concentrations might stimulate different subtypes of opioid recep-tors.The effects of morphine in low concentrations are associated with the acti-vation of potassium channel,whereas the effects of morphine at high concentra-tions are associated with the activation of potassium channel,calcium channel orcalcium activated potassium channel.The action of opioid receptor was clo-sely related to α adrenoreceptors.
出处
《生理学报》
CAS
CSCD
北大核心
1990年第4期323-330,共8页
Acta Physiologica Sinica
基金
国家自然科学基金资助课题
关键词
心肌动作电位
吗啡
morphine
action potential duration
effective refractory period
opioid receptor subtype
ion channel
