Gordon B, Daw N, Parkinson D
Institute of Neuroscience, University of Oregon, Eugene 97403.
Brain Res Dev Brain Res. 1991 Sep 19;62(1):61-7. doi: 10.1016/0165-3806(91)90190-t.
We have examined the effect of age on the binding of (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10-imine maleate (MK-801) in the cat visual cortex. We hypothesized that this binding might change with age because: (1) MK-801 binds to a site associated with the N-methyl-D-aspartate (NMDA) receptor; (2) the NMDA receptor complex has been implicated in neural plasticity; (3) plasticity in the cat visual cortex is age dependent. We used standard receptor binding techniques to measure MK-801 binding in membrane homogenates in cats aged 7 days (d), 21 d, 43 d, 83 d, 7-8 months (mo) and over 2 years. Glutamate (100 microM), glycine (30 microM) and spermidine (20 microM) were used to enhance binding. We found that MK-801 binding is maximal at about 6 weeks of age, decreases slightly by 83 days and then decreases more dramatically in adults. Saturation analysis showed that the of binding with age resulted from variation in number of binding sites and not from variation in affinity. The ability of Mg2+ to inhibit MK-801 binding did not change with age. Dark rearing did not alter the development of MK-801 binding sites.
我们研究了年龄对（+）-5-甲基-10,11-二氢-5H-二苯并[a,d]环庚烯-5,10-亚胺马来酸盐（MK-801）在猫视觉皮层中结合的影响。我们推测这种结合可能会随年龄变化，原因如下：（1）MK-801与N-甲基-D-天冬氨酸（NMDA）受体相关的位点结合；（2）NMDA受体复合物与神经可塑性有关；（3）猫视觉皮层的可塑性取决于年龄。我们使用标准受体结合技术来测量7天（d）、21 d、43 d、83 d、7 - 8个月（mo）及2岁以上猫的膜匀浆中MK-801的结合情况。使用谷氨酸（100 microM）、甘氨酸（30 microM）和亚精胺（20 microM）来增强结合。我们发现MK-801结合在约6周龄时达到最大值，到83天时略有下降，然后在成年猫中下降更为显著。饱和分析表明，结合随年龄的变化是由于结合位点数目的变化，而非亲和力的变化。Mg2+抑制MK-801结合的能力不会随年龄改变。暗饲养不会改变MK-801结合位点的发育。
