Histamine levels and activities of histamine metabolizing enzymes in mammalian ocular tissues: comparison between day and night.
Iris, ciliary body, choroid and retina of the cow, rabbit and man contain histamine; the retinas are less rich in histamine (55-135 ng/g tissue) than the uvea (209-3073 ng/g tissue). The tissues show no diamine oxidase activity, no or marginal histidine decarboxylase activity, and well expressed histamine-N-methyltransferase activity. The killing of the rabbits at noon, light-midnight and dark-midnight revealed some day-night and light-dark dependent variations in both histamine content and histamine-N-methyltransferase activity in the iris-ciliary body, choroid and retina. It is suggested that histamine in mammalian eye may be of some functional importance.
Nowak
J Z
JZ
Department of Biogenic Amines, Polish Academy of Sciences, Lodź, Poland.
Soćko
R
R
D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002829:Choroid / Q000201:enzymology / Q000378:metabolism; D002924:Ciliary Body / Q000201:enzymology / Q000378:metabolism; D002940:Circadian Rhythm; D005123:Eye / Q000201:enzymology / Q000378:metabolism*; D006632:Histamine / Q000378:metabolism*; D006637:Histamine N-Methyltransferase / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007498:Iris / Q000201:enzymology / Q000378:metabolism; D011817:Rabbits; D012160:Retina / Q000201:enzymology / Q000378:metabolism
D006632:Histamine; D006637:Histamine N-Methyltransferase