Distribution of melatonin MT1 receptor immunoreactivity in human retina.
Melatonin is synthesized in the pineal gland and retina during the night. Retinal melatonin is believed to be involved in local cellular modulation and in regulation of light-induced entrainment of circadian rhythms. The present study provides the first immunohistochemical evidence for the localization of melatonin 1a-receptor (MT1) in human retina of aged subjects. Ganglion, amacrine, and photoreceptor cells expressed MT1. In addition, MT1 immunoreactivity was localized to cell processes in the inner plexiform layer and to central vessels of the retina, as well as to retinal vessels but not to ciliary or choroidal vessels. These results support a variety of cellular and vascular effects of melatonin in the human retina. Preliminary evidence from patients with Alzheimer's disease (AD) revealed increased MT1 immunoreactivity in ganglion and amacrine cells, as well as in vessels. In AD cases photoreceptor cells were degenerated and showed low MT1 expression.
Savaskan
Egemen
E
Department of Gerontopsychiatry, Psychiatric University Clinic, University of Basel, Wilhelm Klein-Strasse 27, CH-4025 Basel, Switzerland. esavaskan@datacomm.ch
Wirz-Justice
Anna
A
Olivieri
Gianfranco
G
Pache
Mona
M
Kräuchi
Kurt
K
Brydon
Lena
L
Jockers
Ralf
R
Müller-Spahn
Franz
F
Meyer
Peter
P
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D044094:Receptors, Melatonin; D012160:Retina / Q000378:metabolism*
D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D044094:Receptors, Melatonin