摘要
本文观察了阿片类物质影响体外培养心肌细胞搏动功能的生化机制。发现阿片物质对心肌细胞的直接作用机制涉及胞内[Ca^(2+)]i浓度和腺苷酸环化酶(AC)活性改变的调节,方式较复杂。广谱型阿片受体激动剂(κ-δ-μ)依托啡促进外钙内流和内钙释放,增加心肌细胞内[Ca^(2+)]i,其他一些阿片物质则未发现此种作用,吗啡,甲硫脑啡肽对AC活性具有双相调节;强啡肽,β-内啡肽则表现为刺激AC活性。AC活性改变受G蛋白亚基Gi和Gs的共同调控,但以Gs为主。
In this study, the mechanisms of differenet direct effects of opiates on myocardial cell was investigated by examining alteration in [Ca2+]i, cAMP content and adenylate cyclase ( AC ) activity in myocardial cell. The experiment results indicated that there is a biphasic change of AC activity in myoeardial cell which response to Morphine and Enkephalin with inhibition and stimulation.B-Endorphin was found to stimulate AC activity whereas Dynorphin shows a complete inhibition in a monotonic fashion. 10-6 mol/L Naloxone bollished the all effects of opiates tested on AC activity but for Dynorphin. Both pertussis Toxin ( PT ) and Cholera Toxin (CT) all increased opiate-induced AC activity, suggesting that GS ahd Gi simultaneously involved in activation of AC. Etorphine, a ligand of k- -u opiate receptor influenced the Ca2+-mobilizing of myocardial cell with cytoplasmic[Ca2+]i rising from the resting level of 63±10.5nmol/L to 337.5±51.2 nmol/L, through Ca2+ influx and release of intracellular Ca-store. Morphine,Enkephalin and β-Endorphin have no significant effects on the elevation of cytoplasmic [Ca2 +]i. We concluded that receptor for these opiates in cultured myocardial cell are coupled to AC through activation of G protein. Ocu'pancy of these receptors produces a novel changes of cAMP level and cytoplasmic [Ca2+]i may be important molecular mechanisms of myocardial cell response to opiates.
出处
《基础医学与临床》
CSCD
1992年第3期33-38,共6页
Basic and Clinical Medicine
基金
国家自然科学基金 9380007
关键词
阿片受体
心肌细胞
腺苷酸环化酶
opiate receptor myocardial cell [Ca21]i AC G-protein
