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Epinephrine: A Potential Neurotransmitter in Retina
Author(s) -
Hadjiconstantinou Maria,
Cohen Joseph,
Neff Norton H.
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb00843.x
Subject(s) - retina , ganglionectomy , medicine , endocrinology , phenylethanolamine n methyltransferase , superior cervical ganglion , catecholamine , epinephrine , phenylethanolamine , dopamine , norepinephrine , neurotransmitter , retinal , stimulation , biology , chemistry , neuroscience , central nervous system , biochemistry , tyrosine hydroxylase , pathology , alternative medicine
Dopamine (DA), norepinephrine (NE), and epinephrine (EPI) are present in rat retina. DA is the major catecholamine, whereas NE and EPI represent − 5% of the DA content. DA is contained in a subpopulation of amacrine cells and has been the subject of numerous studies. We investigated the origin and properties of NE and EPI in retina. Following superior cervical ganglionectomy, there was a decrease in NE content, but no decrease in EPI or phenylethanolamine‐ N ‐methyltransferase (PNMT) activity. PNMT in retina has many of the substrate‐specificity and inhibitor‐sensitivity characteristics of other tissues. Enzyme activity is enhanced in newborn rats by treatment with dexamethasone. Exposure to a lighted environment increases retinal EPI in normal and superior cervical ganglionectomized rats. EPI content increased for more than 2 h in a lighted environment. We conclude that most of the NE is contained within the sympathetic neurons that innervate the eye from the superior cervical ganglion, whereas EPI is contained in retinal elements that are responsive to photic stimulation.