Shen Yin, Chen Ling, Ping Yong, Yang Xiong-Li
Institute of Neurobiology, Institute of Brain Science, Fudan University, 220 Handan Road, Shanghai 200433, PR China.
Brain Res Bull. 2005 Nov 30;67(6):492-7. doi: 10.1016/j.brainresbull.2005.07.013. Epub 2005 Aug 26.
Effects of glycine on ON type rod-dominant bipolar cells (RBCs) were studied in isolated, superfused carp retina by intracellular recording technique and in carp retinal slice preparation by whole cell recording. Glycine of 4mM hyperpolarized RBCs and potentiated their light responses to large light spots, which was reversed by co-application of 10 microM strychnine. It was further found that illumination of the receptive field surround did not affect the depolarizing center response of RBCs. The above result therefore suggests that glycine modulates the center response of RBCs. Focal application of glycine to either dendrites or axon terminals of RBCs failed to induce any currents in both isolated cell and retinal slice preparations. On the other hand, glycine of 4mM increased the amplitude of the scotopic electroretinographic PIII component, which reflects the activity of rod photoreceptors. It seems likely that modulation by glycine of the RBC center response may be in part ascribed to a consequence of the potentiation of rod responses by glycine.
通过细胞内记录技术在分离的、灌流的鲤鱼视网膜中，以及通过全细胞记录在鲤鱼视网膜切片标本中，研究了甘氨酸对ON型视杆主导双极细胞（RBCs）的影响。4mM的甘氨酸使RBCs发生超极化，并增强了它们对大光斑的光反应，10μM士的宁共同应用可逆转这种作用。进一步发现，光照感受野周边并不影响RBCs的去极化中心反应。因此，上述结果表明甘氨酸调节RBCs的中心反应。在分离细胞和视网膜切片标本中，向RBCs的树突或轴突终末局部施加甘氨酸均未能诱导出任何电流。另一方面，4mM的甘氨酸增加了反映视杆光感受器活性的暗视视网膜电图PIII成分的幅度。甘氨酸对RBCs中心反应的调节作用似乎部分归因于甘氨酸对视杆反应的增强作用。
