title: Photonegative response in brown planaria (Dugesia tigrina) following regeneration.
abstract: The photonegative response was investigated in regenerated brown planaria (Dugesia tigrina). Old, middle, and young animals were tested, bisected into heads and tails, and allowed to regenerate. Different regeneration times affected function, with generally older planaria achieving full functionality of the photonegative response before younger planaria. Counterintuitively, the heads of the middle and young lost this function initially (despite only needing to regenerate their tails) and regained it over time. The size of the animal was not a factor in the photonegativity response. The biological basis for the photonegative response is complex, requiring nervous and locomotive system function and integration. Using the heads from young planaria may serve as a model in aging, degenerative diseases, or environmental toxins.
authors.affiliation: Neurology Service/111H, VA North Texas Health Care System, 4500 S. Lancaster Rd., Dallas, TX 75216-7191, USA.
authors.forename: Barbara D
authors.initials: BD
authors.lastname: Dasheiff
authors.forename: Richard M
authors.initials: RM
authors.lastname: Dasheiff
mesh_terms: D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology / Q000528:radiation effects*; D008027:Light; D010775:Photic Stimulation; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology / Q000528:radiation effects; D010932:Planarians / Q000502:physiology / Q000528:radiation effects*; D012038:Regeneration / Q000502:physiology*