Noradrenaline- and melatonin-mediated regulation of pigment aggregation in fish melanophores.
The effects of melatonin and noradrenaline (NA) on bi-directional melanosome transport were analysed in primary cultures of melanophores from the Atlantic cod. Both agents mediated rapid melanosome aggregation, and by using receptor antagonists, melatonin was found to bind to a melatonin receptor whereas NA binds to an alpha2-adrenoceptor. It has previously been stated that melatonin-mediated melanosome aggregation in Xenopus is coupled with tyrosine phosphorylation of a so far unidentified high molecular weight protein and we show that although acting through different receptors and through somewhat different downstream signalling events, tyrosine phosphorylation is of the utmost importance for melanosome aggregation mediated by both NA and melatonin in cod melanophores. Together with cyclic adenosine 3-phosphate-fluctuations, tyrosine phosphorylation functions as a switch signal for melanosome aggregation and dispersion in these cells.
Aspengren
Sara
S
Department of Zoology and Zoophysiology, Göteborg University, Göteborg, Sweden. sara.aspengren@zool.gu.se
Sköld
Helén Nilsson
HN
Quiroga
Gabriela
G
Mårtensson
Lena
L
Wallin
Margareta
M
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005399:Fishes / Q000378:metabolism*; D019833:Genistein / Q000494:pharmacology; D007529:Isoflavones / Q000494:pharmacology; D008547:Melanophores / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology*; D010860:Pigments, Biological / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
D000316:Adrenergic alpha-Agonists; D004791:Enzyme Inhibitors; D007529:Isoflavones; D010860:Pigments, Biological; C040641:genistin; D019833:Genistein; D008550:Melatonin; D009638:Norepinephrine