Nucci C, Morrone L, Rombolà L, Nisticò R, Piccirilli S, Cerulli L
Department of Biopathology and Diagnostic Imaging, Physiopathological Optics, University of Rome Tor Vergata, Rome, Italy.
Toxicol Lett. 2003 Apr 4;139(2-3):163-73. doi: 10.1016/s0378-4274(02)00430-7.
The lateral geniculate nucleus (LGN) is the thalamic relay of retinal inputs to the visual cortex. It contains a rich array of brain terminals, which modulate the visual signals to the cortex. Several data have documented that beside cholinergic, GABA-nergic, istaminergic, serotoninergic, and glutamatergic signals, the LGN contains also fibers and interneurons expressing the enzyme that produces nitric oxide (NO). Here, we review the documented physiological roles of NO in the transmission of visual inputs to the cortex and in the processes of activity-dependent refinement of LGN connections. Moreover we focus on the recently suggested role of NO in processes of neurotoxicity in the LGN. Particular relevance is given to studies documenting that, through an excitotoxic cascade, NO triggers apoptosis in the LGN of new-born rats deprived of vision in one eye. Data are also discussed on a possible role of NO in the mechanisms of LGN neuronal loss induced by glaucoma. We believe that a better understanding of the role of NO in the LGN may contribute to discover new experimental strategies for the treatment of degenerative ophthalmic diseases.
外侧膝状体核（LGN）是视网膜输入信号至视觉皮层的丘脑中继站。它包含丰富的脑终末，这些终末调节传至皮层的视觉信号。多项数据表明，除了胆碱能、γ-氨基丁酸能、组胺能、5-羟色胺能和谷氨酸能信号外，LGN还含有表达产生一氧化氮（NO）的酶的纤维和中间神经元。在此，我们综述了NO在视觉输入信号传至皮层以及LGN连接的活动依赖性精细化过程中已被证实的生理作用。此外，我们关注NO在LGN神经毒性过程中最近被提出的作用。特别强调了一些研究，这些研究表明，通过兴奋性毒性级联反应，NO可触发新生大鼠单眼失明后LGN中的细胞凋亡。还讨论了关于NO在青光眼诱导的LGN神经元丢失机制中可能作用的数据。我们认为，更好地理解NO在LGN中的作用可能有助于发现治疗退行性眼科疾病的新实验策略。
