Photoreceptor-like outer segments in the pineal organ of the lovebird, Uroloncha domestica (Aves: passeriformes). A scanning electron microscopic study.
In the pineal organ of the lovebird, Uroloncha domestica, bulbous, cup-shaped and elongated outer segments of photoreceptor-like pinealocytes are demonstrated by scanning electron microscopy. These scarce outer segments, 4-11 micron in length, extend into the pineal lumen. The present structural observations speak in favor of photosensitive pinealocytes in the pineal organ of Uroloncha domestica. The relation of the photoreceptor-like pinealocytes to acetylcholinesterase-positive nerve cells and a nervous connection between the pineal and the brain indicate that the pineal organ of this passeriform species may be the site of neuroendocrine and photoreceptive functions.
D000110:Acetylcholinesterase; D000818:Animals; D001717:Birds / Q000033:anatomy & histology*; D008855:Microscopy, Electron, Scanning; D009474:Neurons; D010786:Photoreceptor Cells / Q000648:ultrastructure*; D010870:Pineal Gland / Q000648:ultrastructure*
D000110:Acetylcholinesterase