Opmeer F A, Peter J, Burbach H, Wiegant V M, van Ree J M
Life Sci. 1982 Jul 26;31(4):323-8. doi: 10.1016/0024-3205(82)90410-6.
The influence of chronic morphine exposure in vitro on the biotransformation of beta-endorphin (beta E) was investigated using the myenteric plexus-longitudinal muscle of guinea-pig ileum. A membrane preparation was incubated with beta E and the degradation of beta E as well as the accumulation of several beta E fragments in the incubation medium were followed with time. The levels of peptides were determined by specific radioimmunoassays after separation by high-pressure liquid chromatography. It was found that exposure to morphine did not affect the disappearance of beta E, but altered the time course of accumulation of beta E fragments. In fact, the accumulation of gamma-endorphin, alpha-endorphin and des-tyrosine1-alpha-endorphin was enhanced, while that of des-tyrosine1-gamma-endorphin was not change. Additionally, the disappearance of gamma-endorphin appeared to be stimulated by morphine exposure. These data provide evidence that the fragmentation of beta E is changed by chronic morphine exposure in such a way that the turnover of gamma-endorphin is increased.
利用豚鼠回肠的肌间神经丛-纵行肌，研究了体外长期暴露于吗啡对β-内啡肽（βE）生物转化的影响。将一种膜制剂与βE一起孵育，并随着时间的推移跟踪βE的降解以及几种βE片段在孵育培养基中的积累情况。通过高压液相色谱分离后，采用特异性放射免疫测定法测定肽的水平。结果发现，暴露于吗啡并不影响βE的消失，但改变了βE片段积累的时间进程。事实上，γ-内啡肽、α-内啡肽和去酪氨酸1-α-内啡肽的积累增强，而去酪氨酸1-γ-内啡肽的积累没有变化。此外，吗啡暴露似乎刺激了γ-内啡肽的消失。这些数据提供了证据，表明长期暴露于吗啡会改变βE的片段化，从而增加γ-内啡肽的周转。
