IMMUNOREACTIVE OPSIN IN THE PINEAL ORGAN OF REPTILES AND BIRDS

  • 1 January 1982
    • journal article
    • research article
    • Vol. 96  (1) , 113-129
Abstract
The presence of opsin was investigated with light microscopic immunocytochemistry in pinealocytes of reptiles and birds (Emys orbicularis, Pseudemys scripta elegans, Lacerta agilis, L. viridis, Gallus domesticus, Columba livia, Melopsittacus undulatus, Serinus canaria, Taeniopyga punctata). The outer segments of pinealocytes selectively bound antiopsin antibody as revealed by indirect immunocytochemical techniques, indicating the occurrence of a rhodopsin-like photopigment in these structures. The results were compared with those obtained in retinal photoreceptors of the same species and in the pineal organ of fishes and amphibians (Cyprinus carpio, Carassius auratus, Rana esculenta). Corresponding to immunoreactive structures seen in the light microscope, typical outer segments on a large number of pinealocytes in most of the reptiles and birds studied were found. The presence of opsin in the numerous well developed pineal outer segments of these reptilian and avian species contradicts the earlier hypothesis on the gradual regression of pineal light sensitive structures in the avian line of evolution.