title: Direct photosensitivity of chick pinealocytes as demonstrated by visinin immunoreactivity.
abstract: Visinin, a calcium-binding protein isolated from the soluble fraction of homogenized chick retinae, has been recognized immunocytochemically in the pinealocytes of various submammals. In the chick pineal organ, continuous environmental light induced an increase in population density of visinin-immunoreactive pinealocytes. In semi-quantitative, dot-immunoblotting analysis, the amount of visinin in the pineal organs of chicks kept under continuous light for 3 days was 4-8 fold more abundant than that under continuous darkness for the same duration. Eye-enucleation and organ culture experiments clarified that this lighting effect was exerted directly on the pineal organ through the skull, and not via the neural pathway including the retinohypothalamic projection. These data suggest the existence of direct photosensitivity in the chick pinealocyte itself and the possible involvement of visinin in photoreception of the pineal organ as well as the retina of chicks.
authors.affiliation: Department of Anatomy, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Goto
authors.forename: K
authors.initials: K
authors.lastname: Yamagata
authors.forename: N
authors.initials: N
authors.lastname: Miki
authors.forename: H
authors.initials: H
authors.lastname: Kondo
mesh_terms: D000818:Animals; D002645:Chickens / Q000502:physiology*; D015151:Immunoblotting; D007150:Immunohistochemistry; D008027:Light; D008297:Male; D009419:Nerve Tissue Proteins / Q000276:immunology* / Q000378:metabolism; D010786:Photoreceptor Cells / Q000502:physiology; D010870:Pineal Gland / Q000166:cytology* / Q000378:metabolism / Q000502:physiology
chemical_list: D009419:Nerve Tissue Proteins; C045140:visinin