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Immunohistological Localization of Mel1a Melatonin Receptor in Pigeon Retina

Authors Sheng W, Weng S, Li F, Zhang Y, He Q, Sheng W, Fu Y, Yan H, Liu K

Received 6 November 2020

Accepted for publication 18 December 2020

Published 5 February 2021 Volume 2021:13 Pages 113—121


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Professor Steven A Shea

Wenlong Sheng,1 Shijun Weng,2 Fei Li,1 Yun Zhang,1 Qiuxia He,1 Wenxiang Sheng,1 Ying Fu,3 Haiyue Yan,4 Kechun Liu1

1Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, People’s Republic of China; 2State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China; 3Shandong Science and Technology Exchange Center, Jinan, People’s Republic of China; 4Shandong Institute of Scientific and Technical Information, Jinan, People’s Republic of China

Correspondence: Wenlong Sheng; Kechun Liu Email;

Background: Melatonin (N-acetyl-5-methoxytryptamine), a significant indoleamine neuromodulator implicated in circadian rhythms and sleep patterns, regulates diverse rhythmic functions via activating its high-affinity G-protein-coupled receptors. However, the detailed cellular expression of the Mel1a receptor in the retina is still a research gap.
Methods: The expression of the Mel1a receptor in pigeon retina was assessed using Western blot analysis and immunofluorescent staining. The cellular localization of the Mel1a receptor was studied using double immunofluorescent staining and laser-scanning confocal microscopy.
Results: Our data suggested that the Mel1a receptor was extensively expressed in the outer segment of Rho4D2-labeled rod and L/M-opsin-labeled red/green cone and in the somata of the CB-labeled horizontal cell, TH-labeled dopaminergic amacrine cell, ChAT-labeled cholinergic amacrine cell, PV-labeled AII amacrine cell, Brn3a-labeled conventional ganglion cell, melanopsin-containing ganglion cell and CRALBP-labeled Müller glial cell. In addition, the Mel1a receptor was diffusely distributed throughout the full thickness of the inner plexiform layer. However, the outer segment of S-opsin-labeled blue cone, the somata of ChX-10-labeled bipolar cell and outer plexiform layer seemed to lack immunoreactivity of the Mel1a receptor.
Conclusion: The finding that multiple types of retinal cells express the Mel1a receptor provides a new neurobiological basis for the participation of melatonin in the regulation of retinal functions through activating the Mel1a receptor.

Keywords: circadian rhythm, retinal Mel1a receptor, cellular localization, diurnal animal

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