Temporal properties of dual-peak responses of mouse retinal ganglion cells and effects of inhibitory pathways.
Dual-peak responses of retinal ganglion cells (RGCs) are observed in various species, previous researches suggested that both response peaks were involved in retinal information coding. In the present study, we investigated the temporal properties of the dual-peak responses recorded in mouse RGCs elicited by spatially homogeneous light flashes and the effect of the inhibitory inputs mediated by GABAergic and/or glycinergic pathways. We found that the two peaks in the dual-peak responses exhibited distinct temporal dynamics, similar to that of short-latency and long-latency single-peak responses respectively. Pharmacological studies demonstrated that the application of exogenous GABA or glycine greatly suppressed or even eliminated the second peak of the cells' firing activities, while little change was induced in the first peak. Co-application of glycine and GABA led to complete elimination of the second peak. Moreover, application of picrotoxin or strychnine induced dual-peak responses in some cells with transient responses by unmasking a second response phase. These results suggest that both GABAergic and glycinergic pathways are involved in the dual-peak responses of the mouse RGCs, and the two response peaks may arise from distinct pathways that would converge on the ganglion cells.
School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China.
Ru-Jia
RJ
Yan
School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China.
Hai-Qing
HQ
Gong
School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China.
Pu-Ming
PM
Zhang
School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China.
Shi-Gang
SG
He
School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China.
Pei-Ji
PJ
Liang
Dual-peak response; Inhibitory pathway; Retinal ganglion cell; Temporal property