Inoue O, Tsukada H, Kobayashi K, Suhara T, Itoh T
Division of Clinical Research, National Institute of Radiological Sciences, Chiba, Japan.
Neuropharmacology. 1991 Oct;30(10):1101-6. doi: 10.1016/0028-3908(91)90139-3.
The effect of swim stress on the in vivo binding of [3H]N-methylspiperone in the striatum of the mouse was investigated. Mice were forced to swim for 5 min at 18 degrees C and the time course of radioactivity in the striatum and cerebellum, following intravenous injection of [3H]N-methylspiperone was measured. The ratio of radioactivity in the striatum to that in the cerebellum was plotted as a function of time for the estimation of in vivo binding to dopamine D2 receptors. Immediately after the swim stress, a significant decrease in binding to D2 receptors in vivo was observed. Neither the KD nor Bmax determined by in vitro binding were altered by swim stress. The time course of the changes in binding, within a 24 hr period, following the swim stress was also studied and a rapid reversal of binding, within 1 hr after the swim stress was observed. In vivo binding of [3H]N-methylspiperone in the cerebral cortex, which appeared to involve serotonin receptors, as well as D2 receptors, was not significantly altered by the swim stress. A saturation study of in vivo binding indicated that the decreases in binding to D2 receptors, due to swim stress, were primarily caused by changes in the apparent affinity rather than in the number of binding sites available in vivo. These results support the hypothesis that micro-environmental factors, including the diffusion barrier to the synapse, might be altered by swim stress.
研究了游泳应激对小鼠纹状体中[3H]N-甲基螺哌隆体内结合的影响。将小鼠置于18摄氏度环境中强迫游泳5分钟，静脉注射[3H]N-甲基螺哌隆后，测量纹状体和小脑中放射性的时间进程。绘制纹状体与小脑中放射性的比值随时间的变化曲线，以评估体内与多巴胺D2受体的结合情况。游泳应激后立即观察到体内与D2受体结合的显著下降。游泳应激未改变通过体外结合测定的KD和Bmax。还研究了游泳应激后24小时内结合变化的时间进程，观察到游泳应激后1小时内结合迅速恢复。游泳应激对大脑皮层中[3H]N-甲基螺哌隆的体内结合没有显著影响，大脑皮层中的结合似乎涉及5-羟色胺受体以及D2受体。体内结合的饱和研究表明，游泳应激导致的与D2受体结合的减少主要是由表观亲和力的变化引起的，而不是体内可用结合位点数量的变化。这些结果支持以下假设：包括突触扩散屏障在内的微环境因素可能会因游泳应激而改变。
