Department of Physiology, Medical University, Sofia, Bulgaria.
Acta Histochem. 2011 Sep;113(5):495-500. doi: 10.1016/j.acthis.2010.04.010. Epub 2010 Jul 5.
The NMDA receptors are ionotropic glutamate receptors that are involved in a variety of functions in the nervous system and in particular in the retina. They are composed of NR1 and NR2 subunits. The NMDA receptors have been fairly well studied in the retina of mammals, however, there is only limited information concerning these receptors in the retinas of lower vertebrates. The aim of the present study was to investigate immunocytochemically the NR1, NR2A and NR2B subunits of the NMDA receptors in the frog retina. Six primary antibodies were used. Three of them were directed to different splice variants of the NR1 subunit and the remaining three variants directed to NR2 subunits. All antibodies showed well expressed labeling in the frog retina. The labels had a punctate character and were located mainly in the inner and the outer plexiform layers. The results obtained indicate that the NR1, NR2A and NR2B subunits of NMDA receptor may participate in the glutamatergic neurotransmission from photoreceptors to second order retinal neurons, as well as from bipolar cells to third order retinal neurons. It has been proposed that in the frog retina, several subtypes of NMDA receptors exist each involved with different functions.
NMDA 受体是离子型谷氨酸受体，它们参与神经系统的各种功能，特别是在视网膜中。它们由 NR1 和 NR2 亚基组成。NMDA 受体在哺乳动物的视网膜中已经得到了相当充分的研究，然而，关于这些受体在较低等脊椎动物的视网膜中的信息却非常有限。本研究的目的是用免疫细胞化学方法研究青蛙视网膜中的 NMDA 受体的 NR1、NR2A 和 NR2B 亚基。使用了六种主要的抗体。其中三种针对 NR1 亚基的不同剪接变体，其余三种变体针对 NR2 亚基。所有抗体在青蛙视网膜中都表现出良好的表达标记。标记具有点状特征，主要位于内丛状层和外丛状层。所得结果表明，NMDA 受体的 NR1、NR2A 和 NR2B 亚基可能参与从光感受器到二级视网膜神经元以及从双极细胞到三级视网膜神经元的谷氨酸能神经传递。已经提出，在青蛙视网膜中，存在几种 NMDA 受体亚型，每种受体都涉及不同的功能。
