Jin Nan Ge, Ribelayga Christophe P
Ruiz Department of Ophthalmology and Visual Science, and.
Ruiz Department of Ophthalmology and Visual Science, and Graduate School of Biomedical Sciences, Program in Neuroscience, Graduate School of Biomedical Sciences, and Neuroscience Research Center, The University of Texas Health Science Center at Houston, Houston, Texas 77030
J Neurosci. 2016 Jan 6;36(1):178-84. doi: 10.1523/JNEUROSCI.3301-15.2016.
Rod photoreceptors are electrically coupled through gap junctions. Coupling is a key determinant of their light response properties, but whether rod electrical coupling is dynamically regulated remains elusive and controversial. Here, we have obtained direct measurements of the conductance between adjacent rods in mouse retina and present evidence that rod electrical coupling strength is dependent on the time of day, the lighting conditions, and the mouse strain. Specifically, we show in CBA/Ca mice that under circadian conditions, the rod junctional conductance has a median value of 98 pS during the subjective day and of 493 pS during the subjective night. In C57BL/6 mice, the median junctional conductance between dark-adapted rods is ∼140 pS, regardless of the time in the circadian cycle. Adaptation to bright light decreases the rod junctional conductance to ∼0 pS, regardless of the time of day or the mouse strain. Together, these results establish the high degree of plasticity of rod electrical coupling over the course of the day. Estimates of the rod coupling strength will provide a foundation for further investigations of rod interactions and the role of rod coupling in the ability of the visual system to anticipate, assimilate, and respond to the daily changes in ambient light intensity.
Many cells in the CNS communicate via gap junctions, or electrical synapses, the regulation of which remains largely unknown. Here, we show that the strength of electrical coupling between rod photoreceptors of the retina is regulated by the time of day and the lighting conditions. This mechanism may help us understand some key aspects of day and night vision as well as some visual malfunctions.
视杆光感受器通过缝隙连接实现电耦合。耦合是其光反应特性的关键决定因素，但视杆电耦合是否受到动态调节仍不清楚且存在争议。在此，我们直接测量了小鼠视网膜中相邻视杆之间的电导，并提供证据表明视杆电耦合强度取决于一天中的时间、光照条件和小鼠品系。具体而言，我们在CBA/Ca小鼠中发现，在昼夜节律条件下，视杆连接电导在主观白天的中值为98皮西门子，在主观夜间为493皮西门子。在C57BL/6小鼠中，暗适应视杆之间的连接电导中值约为140皮西门子，与昼夜节律周期中的时间无关。无论一天中的时间或小鼠品系如何，适应强光都会使视杆连接电导降低至约0皮西门子。这些结果共同证明了视杆电耦合在一天中具有高度的可塑性。对视杆耦合强度的估计将为进一步研究视杆相互作用以及视杆耦合在视觉系统预测、同化和响应环境光强度每日变化能力中的作用提供基础。
中枢神经系统中的许多细胞通过缝隙连接或电突触进行通讯，其调节在很大程度上仍不清楚。在此，我们表明视网膜视杆光感受器之间的电耦合强度受一天中的时间和光照条件调节。这一机制可能有助于我们理解昼夜视觉的一些关键方面以及一些视觉功能障碍。
