Immunohistological localization of melatonin in the pineal gland and retina of the rat.

An incubation procedure for the demonstration of melatonin is described using freeze-dried, unfixed material embedded in vacuum directly in glycolmethacrylate. The results indicate the binding of melatonin in the nucleus of pineal parenchymal cells and in the outer nuclear layer of the retina of rats; binding is greater at night than during the day.