Dong Y N, Mao M H, Wang X M, Han J S
Neuroscience Research Institute, Beijing Medical University, Beijing 100083.
Sheng Li Xue Bao. 1998 Dec;50(6):663-70.
The effect of repetitive 100 Hz EA stimulation on the characteristics of binding of kappa opioid receptors in discrete brain regions and the spinal cord of rats was investigated by radioligand binding assay. 100 Hz EA was administered once a day (30 min) for 7 d. Changes in Bmax and Kd of kappa opioid receptors of 4 discrete brain regions (cortex, midbrain, pons-medulla and striatum) and spinal cord were observed at d 1, 3, 5 and 7, respectively. It was found that the numbers (Bmax) of kappa opioid receptors of all the brain regions observed were decreased during the development of 100 Hz EA tolerance with a differential time course. In rat cortex and pons-medulla, a marked down regulation of kappa opioid receptors occurred within 24 h and remained at a low level throughout the observation. The Bmax of kappa receptor in spinal cord showed a bell-shaped curve, i.e., up regulation in the first 5 days and down regulation at d 7. In contrast a slow and steady down regulation was found in the midbrain and striatum, matching the course of development of 100 Hz EA tolerance. No significant changes in Kd of [3H]-U69593 were found except for a decrease of Kd in midbrain. In conclusion, administration of 100 Hz EA 30 min per day for 7 consecutive days resulted in a significant down regulation of kappa opioid receptor in CNS, especially in midbrain and striatum.
采用放射性配体结合分析法，研究了重复100Hz电针刺激对大鼠离散脑区和脊髓中κ阿片受体结合特性的影响。100Hz电针每天给药一次（30分钟），持续7天。分别在第1、3、5和7天观察4个离散脑区（皮层、中脑、脑桥-延髓和纹状体）和脊髓中κ阿片受体的Bmax和Kd变化。结果发现，在100Hz电针耐受形成过程中，所有观察脑区的κ阿片受体数量（Bmax）均下降，且时间进程不同。在大鼠皮层和脑桥-延髓中，κ阿片受体在24小时内显著下调，并在整个观察期内维持在低水平。脊髓中κ受体的Bmax呈钟形曲线，即在第1至5天上调，第7天下调。相反，中脑和纹状体中发现缓慢而稳定的下调，与100Hz电针耐受的发展过程相符。除中脑Kd降低外，[3H]-U69593的Kd未发现显著变化。总之，连续7天每天给予100Hz电针30分钟可导致中枢神经系统中κ阿片受体显著下调，尤其是在中脑和纹状体。
