Injection of MK-801 affects ocular dominance shifts more than visual activity
Injection of MK-801 affects ocular dominance shifts more than visual activity
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DOI：
10.1152/jn.1999.81.1.204
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发表时间：
1999-01-01
影响因子：
2.5
通讯作者：
Czepita, D
中科院分区：
文献类型：
--
作者：
Daw, NW;Gordon, B;Czepita, D
在眼优势变化敏感性高峰期，每天两次（早晨和中午）肌内注射N-甲基-D-天冬氨酸（NMDA）拮抗剂MK-801。然后在每次注射后将它们暴露于光下，其中一只眼睛闭合4小时。这些幼猫的眼优势明显低于注射生理盐水并在相同年龄的相同时间暴露于光照的幼猫。在记录用于眼优势直方图的细胞样本后，向小猫注射与饲养期间使用的相同剂量的MK-801，以观察其对视觉皮层中单细胞活性的影响。在大多数细胞（7/13）中，活性无显著变化。仅在少数（3/13）细胞中观察到活性降低的阳性证据。在单独的一系列实验中，测量了视皮层细胞对NMDA或α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）离子电渗的剂量-反应曲线，并测量了注射MK-801对这些曲线的影响。MK-801在与眼优势实验中使用的剂量相似的剂量下，对NMDA的剂量-反应曲线具有显著影响，但对AMPA的剂量-反应曲线或细胞的视觉反应几乎没有影响。我们的结论是，眼优势的转变可以显着减少的治疗，对视觉皮层细胞的活性水平几乎没有影响，但具体影响细胞的反应，而不是对AMPA的反应。
Kittens were given intramuscular injections of the N-methyl-D-aspartate (NMDA) antagonist MK-801 twice daily (morning and midday) during the peak of the period of susceptibility for ocular dominance changes. They were then exposed to light with one eye closed for 4 h after each injection. The ocular dominance of these kittens was shifted significantly less than that of kittens injected with saline and exposed to light over the same period at the same age. After recording a sample of cells for an ocular dominance histogram, the kittens were injected with the same dose of MK-801 that was used during rearing to observe its effect on the activity of single cells in the visual cortex. In the majority of cells (7/13) there was no significant change in activity. Positive evidence for a reduction in activity was seen in only a minority (3/13) of cells. In a separate series of experiments, dose-response curves were measured for cells in the visual cortex in response to iontophoresis of NMDA or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and the effect of an injection of MK-801 on these curves was measured. MK-801, at doses similar to those used in the ocular dominance experiments, had a significant effect on the dose-response curves for NMDA, but little effect on the dose-response curves for AMPA, or the visual responses of the cells. We conclude that ocular dominance shifts can be reduced significantly by a treatment that has little effect on the level of activity of cells in the visual cortex but does specifically affect the responses of the cells to NMDA as opposed to the responses to AMPA.