These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Immunohistochemical localization of L-dopa and aromatic L-amino acid-decarboxylase in the rat retina.
    Author: Nguyen-Legros J, Krieger M, Simon A.
    Journal: Invest Ophthalmol Vis Sci; 1994 Jun; 35(7):2906-15. PubMed ID: 8206708.
    Abstract:
    PURPOSE: The purpose of this study was threefold: to determine if some catecholaminergic amacrine cells of the rat retina use L-DOPA as their neurotransmitter, especially the small (2CA) cells that are immunoreactive to tyrosine hydroxylase but not to dopamine; to understand better the possible existence of serotoninergic cells in the rat retina; and to clarify the role of serotonin in the metabolism of melatonin. METHODS: Immunohistochemistry using antibodies against tyrosine hydroxylase (TH), L-DOPA, aromatic L-amino acid decarboxylase (AADC), dopamine (DA), and tyramine in rat retinal wholemounts, serial sections, and various combinations of double labeling. RESULTS: Paired wholemounts immunoreacted with anti-TH/AADC antibodies did not show a significant difference in densities of TH+ and AADC+ amacrine cells. All the TH+ cells exhibited AADC immunoreactivity. There were no AADC-immunoreactive cells lacking TH. A few TH+ cells exhibited L-DOPA immunoreactivity; they also contained AADC. The inner segments of photoreceptor cells were labeled by the anti-AADC antibody. The antibody to tyramine did not label any cells in the rat retina. CONCLUSIONS: L-DOPA can be excluded as a candidate active substance for the small TH+ amacrine cells that do not exhibit DA-immunoreactivity. The L-DOPA-immunoreactivity restricted to a small number of large TH+ amacrine cells probably does not represent an end product. Tyramine also does not appear to constitute a neurotransmitter in the rat retina. We confirm that there are no serotonin-synthesizing amacrine cells in the rat retina. The localization of AADC-immunoreactivity in the photoreceptor cell inner segments is possibly related to the biosynthetic pathway of melatonin from 5-hydroxytryptophan.
    [Abstract] [Full Text] [Related] [New Search]