Distribution of 2-.

Using in vitro autoradiography, the distribution of 2-[125I]iodomelatonin (IMEL) binding sites in the brain of the pied flycatcher and the zebra finch was examined. The results show IMEL binding in retinofugal, tectofugal and thalamofugal brain areas of the visual system. Additionally, IMEL binding sites were detected in the ectostriatum, the thalamus, the mesencephalon and the limbic system. No IMEL binding could be demonstrated in the pineal gland, the hippocampus, the nucleus suprachiasmaticus, the visual wulst or the pituitary.