Cellular and Molecular NeuroscienceResearch PaperMelatonin inhibits tetraethylammonium-sensitive potassium channels of rod ON type bipolar cells via MT2 receptors in rat retina
Research Highlights
▶MT2 melatonin receptor is expressed on rat retinal Rod-ON-BCs. ▶Melatonin selectively suppresses TEA-sensitive K+ current component in Rod-ON-BCs. ▶Ca2+-dependent PLC/IP3/PKC signaling pathway mediates the melatonin effect.
Section snippets
Experimental procedures
All experimental procedures described here were in accordance with the National Institute of Health (NIH) guidelines for the Care and Use of Laboratory Animals (NIH Publications No. 80-23) revised 1996 and the guidelines of Fudan University on the ethical use of animals. During this study all efforts were made to minimize the number of animals used and their suffering. Male Sprague–Dawley rats weighing 100∼150 g were obtained from SLAC Laboratory Animal Co. Ltd (Shanghai, China) and maintained
Expression of MT2 receptors on Rod-ON-BCs
Expression of MT2 receptors on Rod-ON-BCs was first examined by double immunofluorescence labeling with the antibodies against MT2 receptors and PKC in both acutely isolated cells and retinal sections. The specificity of the MT2 antibody was tested in our previous study by Western blot analysis and immunocytochemistry in isolated RGCs (Zhao et al., 2010). Fig. 1A1–4 show a typical isolated Rod-ON-BC, which was characterized by short dendrites emerging at one end of the soma and a long axon with
Expression of MT2 receptors on rat Rod-ON-BCs
MT2 receptors are widely expressed in both mammalian and non-mammalian retinas (Reppert et al., 1995, Wiechmann et al., 2004, Alarma-Estrany and Pintor, 2007, Savaskan et al., 2007, Huang et al., 2005, Ping et al., 2008, Zhao et al., 2010). Consistent with the observation that MT2 receptors are functionally expressed in Rod-ON-BCs of carp (Ping et al., 2008), the present work, by double immunofluorescence labeling experiments in isolated cell and retinal section preparations, demonstrated for
Acknowledgments
This work was supported by grants from the National Program of Basic Research sponsored by the Ministry of Science and Technology of China (2006CB500805; 2007CB512205; 2011CB504602), the Natural Science Foundation of China (31070966; 30900427; 30870803; 30930034), Pujiang Talent Project of the Shanghai Science and Technology Committee (08PJ1401600), and the 211 Project sponsored by the Ministry of Education of China.
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