Multiple identified peptidergic interneurons express a novel pigment-dispersing hormone in the Daphnia brain and visual ganglia, some showing evidence for clock-neuron functions
2009 (English)In: Comparative Biochemistry and Physiology A, ISSN 1095-6433, E-ISSN 1531-4332, Vol. 153A, no 2, suppl. 1, S156-S157 p.Article in journal (Refereed) Published
Postgenomic, precursor, expressed sequence tag, and mass spectrometric peptidomic analyses allowed us to identify a single gene leading to a novel 18mer-isoform of a bety-type pigment-dispersing hormone (PDH) that is identical in two waterflea species, Daphnia magna and Daphnia pulex. PDH is restricted to interneurons, ten types in the brain and two types in the visual ganglia, and does not occur in neurosecretory cells connected to neurohaemal areas. The neurons individually identified by immunohistochemistry (IHC) were virtually identical in terms of their positions and projection patterns in both species. Whereas the brain neurons are found associated with almost all major neuropils incl. the central body, the visual ganglia neurons adjacent to and innervating the medulla closely resemble the insect so-called pigment-dispersing factor medulla lateral neurons based upon positional and projection criteria. Since the latter neurons are established members of insect circadian clock systems, we analysed these neurons for IHC-detectable circadian changes. Preliminary results under 12:12 h light dark cycles showed significant circadian changes in numbers and staining intensities of the Daphnia medulla PDH neurons. These PDH neurons comprise a simple system currently studied in more depth in behavioural contexts. The discovered homologies to PDH-systems in decapod crustaceans and the well known clock system in several insects suggest evolutionary conservation of an ancient peptidergic interneuronal system in arthropods.
Place, publisher, year, edition, pages
2009. Vol. 153A, no 2, suppl. 1, S156-S157 p.
Research subject Zoology
IdentifiersURN: urn:nbn:se:su:diva-34741DOI: 10.1016/j.cbpa.2009.04.311OAI: oai:DiVA.org:su-34741DiVA: diva2:285369
ProjectsCarl Tryggers Stiftelse