ABSENCE OF INDOLEAMINE-ACCUMULATING NEURONS IN THE RETINA OF HUMANS AND CYNOMOLGUS MONKEYS

Indoleamine-accumulating neurons have previously been detected in cats, rabbits, goldfish, chicken, pigeons, and Cebus monkeys, and were therefore also looked for in humans and an Old World monkey, Cynomolgus irus. The monkey eyes were injected intravitreally with 50 μg 5,6-dihydroxytryptamine, 5 μg α-methylnoradrenaline, or both drugs simultaneously. The human retinas were incubated in either drug. Previous observations on the distribution of dopaminergic neurons were confirmed in the two species, but no indoleamine-accumulating neurons were detected. The result emphasizes the similarity between human and Old World monkey retinas and contrasts them with the retina of the New World monkeys. © 1979 Springer-Verlag.