title: Xenopus tadpole melanophores are controlled by dark and light and melatonin without influence of time of day.
abstract: Melanophores were studied in tadpoles of the South African clawed toad, Xenopus laevis, during the first week after hatching (stages 46-49) at 25 degrees C. The tadpoles had melanophores with dispersed melanosomes in the light and punctate melanophores in the dark in LD 12:12. The melanophores remained punctate in constant dark and the melanosomes remained dispersed in constant light. Lights-out (in the light-time of LD 12:12) caused the melanophores to become punctate, which occurred more quickly than the dispersion of melanosomes, which commenced when the lights were turned on (in the dark-time of LD 12:12). Melanophores with dispersed melanosomes in tadpoles (in constant light) became punctate in response to a series of melatonin concentrations (0.2-5 ng/ml) in their bathing water irrespective of the time of day melatonin was administered. An image-analysis technique for assessing melanophore responses was tested.
authors: Biology Department, Temple University, Philadelphia, PA 19122.
authors: S
authors: S
authors: Binkley
authors: K
authors: K
authors: Mosher
authors: F
authors: F
authors: Rubin
authors: B
authors: B
authors: White
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D007814:Larva / Q000502:physiology; D008027:Light; D008547:Melanophores / Q000187:drug effects / Q000502:physiology*; D008550:Melatonin / Q000494:pharmacology*; D008675:Metamorphosis, Biological; D014982:Xenopus laevis
chemical_list: D008550:Melatonin