Czepita D, Daw N W
Department of Ophthalmology and Visual Science, Yale University Medical School, New Haven, CT 06520-8061, USA.
Brain Res. 1996 Jul 22;728(1):7-12.
Kittens were monocularly deprived to give a partial shift in the ocular dominance histograms from their visual cortices. Responses were measured for the normal and deprived eyes at a variety of contrasts, and curves fitted to give measurements of background activity and peak visual response. The N-methyl-D-aspartate (NMDA) antagonist D-2-amino-5-phosphonovalerate (APV) was then applied, and the effect on the contrast-response curves was measured, and compared in the two eyes. In normal animals, the effect of APV on the contrast-response curve was similar in the two eyes. In monocularly deprived animals, on average, peak visual response was affected similarly in the two eyes, although there was wide variability from cell to cell. When the effect of APV on background activity was measured, there was difference between the normal and deprived eyes. APV reduced background activity in the normal eye more than it reduced background activity in the deprived eye. In other words, the NMDA contribution to background activity in the deprived eye was reduced compared to the NMDA contribution to background activity in the normal eye. This could represent a reduction of NMDA receptors in the pathway from the deprived eye, like the reduction of acetylcholine receptors associated with the losing input at the neuromuscular junction before the nerve is eliminated.
将小猫单眼剥夺，使其视皮层的眼优势直方图发生部分偏移。在各种对比度下测量正常眼和剥夺眼的反应，并拟合曲线以测量背景活动和视觉反应峰值。然后应用N-甲基-D-天冬氨酸（NMDA）拮抗剂D-2-氨基-5-磷酸戊酸（APV），测量其对对比度反应曲线的影响，并在两只眼睛之间进行比较。在正常动物中，APV对对比度反应曲线的影响在两只眼睛中相似。在单眼剥夺的动物中，平均而言，两只眼睛的视觉反应峰值受到的影响相似，尽管细胞间存在很大差异。当测量APV对背景活动的影响时，正常眼和剥夺眼之间存在差异。APV降低正常眼背景活动的程度大于降低剥夺眼背景活动的程度。换句话说，与NMDA对正常眼背景活动的贡献相比，NMDA对剥夺眼背景活动的贡献减少了。这可能代表剥夺眼通路中NMDA受体的减少，类似于在神经消除之前神经肌肉接头处与失去输入相关的乙酰胆碱受体的减少。
