Orexin-B modulates synaptic transmission of rod bipolar cells in rat retina
Gong Zhang; Xiao-Hua Wu; Guo-Zhong Xu,; Shi-Jun Weng; Xiong-Li Yang; Yong-Mei Zhong
2017-07
Conference Name2017年第二届曲阜视觉科学会议
Conference Date2017.7.1
Conference Place曲阜
Abstract

PURPOSE: Orexin-A, -B play a crucial role in arousal and feeding by activating two G-protein-coupled receptors: OX1R and OX2R. Orexins and orexin receptors are expressed in retinal neurons. Indeed, orexins have been found to modulate the activity of amacrine and ganglion cells in the inner retina. However, the function of these peptides in the outer retina remains unknown. In this work, we investigated whether and how orexin-B modulates synaptic transmission of rod-dominant ON type bipolar cells (RBCs)in the outer retina of rat.
METHODS: The in vivo scotopic flash electroretinogram (ERG) recordings were conducted to monitor the effect of orexin-B on RBC activity. Whole cell patch-clamp recording techniques in both retinal slices and dissociated RBCs were used to investigate the effect of orexin-B on synaptic transmission of RBCs.
RESULTS: Intravitreal injection of orexin-B increased the amplitudes of the scotopic ERG b-wave, a reflection of RBC activity. Consistently, patch clamp recordings in rat retinal slices further showed that orexin-B potentiated the responses of RBCs to simulated light flashes, which could avoid presynaptic and lateral interference from photoreceptors and horizontal cells. Effects of orexin-B on GABAergic synaptic transmission were then examined. Presynaptically, orexin-B suppressed GABA receptor-mediated inhibitory postsynaptic currents (IPSCs) of RBCs in retinal slices. Postsynaptically, as whole-cell recordings and calcium imaging from isolated RBCs showed, orexin-B suppressed GABAC receptor-, but not GABAA receptor-, mediated currents, which was blocked by the OX1R and OX2R antagonists. The orexin-B-induced inhibition of GABAC currents was likely mediated by a Gi/o/PC-PLC/Ca2+-independent PKC signaling pathway, as such inhibition was absent when each step of the above-pathway was blocked with GDP-β-S/pertussis toxin (for Gi/o), D609 (for PLC), bisindolylmaleimide IV (for PKC)/rottlerin (for PKCδ), respectively.
CONCLUSIONS: The orexin-B-induced potentiation of RBC activity may improve visual acuity and contrast sensitivity of the animal during the dark period (wake phase).

Keywordorexin-B GABA receptor rod-dominant ON type bipolar cells retina neuromodulation
Language英语
Document Type会议论文
Identifierhttp://ir.psych.ac.cn/handle/311026/22096
Collection心理所主办、承办、协办学术会议_2017年第二届曲阜视觉科学会议_会议摘要
AffiliationInstitutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University
Recommended Citation
GB/T 7714
Gong Zhang,Xiao-Hua Wu,Guo-Zhong Xu,,et al. Orexin-B modulates synaptic transmission of rod bipolar cells in rat retina[C],2017.
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