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M Ohmasa, T Saito; Effects of Acetylcholine and Its Analogs on Intracellular Calcium Level in the Regenerating Retina . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4759.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Acetylcholine (ACh) has been shown to be involved in many aspects of developmental processes of the CNS through changes in the intracellular Ca2+ ion concentrations ([Ca2+]i) . To investigate whether ACh is also involved in the regenerating processes of adult newt retina, we examined the effects of ACh on [Ca2+]i in the regenerating retina using Ca2+ imaging techniques and the time course of appearance of ACh receptors (AChRs) during regeneration using immunohistochemical techniques. Methods: We incubated living slice preparations of regenerating retinas at various stages with a Ca2+-sensitive fluorescent dye (Fura-2). We calculated the 340nm/380nm fluorescence intensity ratio to estimate relative changes in [Ca2+]i. Regenerating retinas were immunostained using antibodies against ACh receptors. Results: At early stage of retinal regeneration, ACh elevated [Ca2+]i in Fura-2-labeled retinal progenitor cells. The ACh-induced [Ca2+]i rise was mainly mediated by activation of an m1- (rather than m2-) type mAChR. This was also supported by the immunohistochemistry. As regeneration proceeded, the number of ACh-responsive cells and peak amplitude of their responses decreased to control levels. Conclusion: The ACh is involved in early regenerating processes as well as developing processes through m1 mAChR-mediated increase in [Ca2+]i .
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